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2/23/2013

Mike Clements 70 inch Reflector


Today was just a wonderful day of discover. This morning my friend Mat had his monthly ATM meeting and I missed out on that due to a commitment I had made to my son.  However, I called when I got home and they were heading out to Steve Dodd's home/property to see Mike Clement's 70 inch F6.2 (I believe, not sure on the F ratio) reflector that he is building. If you haven't heard of Mike's project, a local news station did a story on it and you can find it at this link. The story is archived so give it a few minutes to load.

Mike was very gracious and allowed us to take pictures and to share. So I here I go on the progress of Mike's 70 inch tremendous project.  I have to state up front, Mike prides himself on keeping his projects very simple, very pragmatic and very relevant.  He uses simple materials that are proven and work. I will share my personal opinion that I think Mike is a mechanical genius. He has not plans but works it out in his mind and goes for it.  The pictures show his ingenuity and genius.

Here you can see the 70 inch reflector put together.  It doesn't have the secondary mirror cell installed, instead up Mike has 3 weights up on the upper ring to stimulate the weight of the secondary.  Here you have in order from left to right, Mat, Josh, Mike, Steve (garage door) and Charlie.



Here is the entire telescope with bags of snow melt and a wood box that is equal to the weight and size of the primary mirror.  The red and white on the end of the scope is something Mike put on just because he could and because it looks cool and doesn't impact the weight or balance point of the scope.



Here is the lower cage with the rocker arms that have four roller points and where the primary mirror will be located. Motions on this scope are terrific for such a large scope. Azmuith had some ice on it and when that melted and was removed it was easy to move the scope. Altitude was also easy though the bar that Mike is going to install will help to move the large scope in both motions.


Here is the entire scope again in front of Steve Dodd's garage (Nova Optical is next door and in his main house).  


 Same shot but man, it is a work of love and beauty.



Here you can see the mirror cell, the bearings, and the two arms that go up and connect to the upper ring and the focuser in the mid right part of the picture.



This is a close up of the base and the front of the bearings. You can see underneath the bearings the first of four rollers which move the bearings. Mike has designed this so well that there is no movement or shaking of the scope after you are done moving it.


Here is the upper ring and the fun red and white nose cone on the end. Just so you know Mike designed the scope so that it breaks into six foot sections so it can be loaded into his trailer and transported. The goal for Mike is to have it at a conference in May in Riverside CA to give it first public light (it will have first light hopefully in the next month and Mike invited all of us to be there so I really hope to be there).




At first I thought this was a finderscope, but Mike will be using a C8 for a finderscope for this truly Monster Dob! This is the focuser and Mike has some work to strengthen the focuser as it flexes somewhat but that will be resolved when he focuses on it over the next couple of weeks.



Here you can see the 29 inch secondary that Mike is going to use.  It is fully completed and when the weather improves here in Utah (who knows when that is) Mike is hoping to install it on the upper ring and remove the three weights that stimulate the weight of the secondary mirror and support.  I can state that the work is first class and inspired.  The only thing I didn't ask was how Mike was going to work out such a large obstruction to the primary. 


Here is the lower cage with the rollers again. Next to the rollers are two bolts that can function to keep the scope from tilting forward (if needed, the scope doesn't have this issue) or to lock or scope in place if needed by screwing down the bolts. 




I include this image so you can see the lower rocker, mirror cell and the arms that connect up to the upper ring.


Mike and Steve were working indoors on this (I have forgotten but I believe this is the finderscope mount).




One questions we had was were was the primary mirror being stored. Mike and Steve showed us and it is in that box covered by tarps just down from the shop.


This is a group shot of us in front of Mikes 70" scope. It is Josh who is making a 30" F3.5 of his own. Me, then Mat and then Mike. Mike was a wonderful host and I wish I had simply recorded all the information he shared on the scope.


Here is make showing us the bolts and knobs he is using to collimate. You can see the pads that the mirror will sit on. Mike isn't going to be using a sling or glue to secure the mirror to the mirror supports. The design makes it to where the mirror won't have a shift.



This may not look like much but if you look close, you can see a ring (three actually) where the crane that Mike has designed to operate off of his pickup will hoist the upper arms in place. Great design again.


A close up of the mirror cell for those interested.


This is the crane that Mike has designed to lift the telescope parts in place. The long black tube on top fits into an attachment that fits into the hitch of his pickup. Mike then makes his pickup into a crane.

Well, that is all the pictures. It was a pleasure to talk and see what Mike has done to build this tremendous scope. Everything is coming together quite well and in March or early April the scope should see first light. Oh, the 31 Nagler will give just over 330x and that is the lowest power eyepiece for the scope right now.  So those more knowledgeable can add their info (Mike, Steve, Mat or Josh) or others if they wish. 

2/17/2013

On Friday, February 15th, 2013 I set up in the backyard since the waxing crescent moon was up and going to a dark site would be mute. Also that evening my friend Mat had two friends and fellow ATMers Jeff Baldwin and if I remember right Doug Christensen from the Stockton Astronomical Society.  I invited them to the back yard at 7:30 p.m. and I had set up and the scope this evening wouldn't travel completely in altitude. I made a silly mistake when loading the alt bearings on so I had to uninstall and then re-install the scope. I was just finishing as they came. I wanted to put the strings on but one of the turn buckles had fallen off and after searching the grass, we decided to leave them off. I collimated using the Howie Glatter 2 inch laser and Tu-Blug.  The scope was collimated and I invited Mat, Jeff and Doug to use the scope. I had to find the missing turn buckle and had a feeling it had fallen off in the office where I store the scope. Sure enough it was there but we left the strings off since it would require a new collimation (personally I would have put them on and re-collimated as the scope needs them or the collimation shifts slightly).

After this we each took turns finding objects and then looking. Jeff used the scope the most I think at my invitation. We spent our time on mostly eye candy materials, and not in any particular order here are some of the objects we observed. There was M103, M35 & NGC 2158, M42, NGC 884 and 869 the Double Cluster, M41, M50, NGC 2392 PN the Eskimo Nebula, NGC 2169, M78 that was not very good when we viewed it and M81 and M82.  To end the night we looked at Regulus and Eta Leonis doubles in Leo.

Jeff and Doug had traveled all night from the Stockton CA area (Lathrop CA) and were tired so around  10:20p.m. they with Mat drove back to Mat's to sleep since they had a weekend working on mirrors and testing mirrors etc.  Mat asked if I wanted help breaking down but I didn't because I had my own agenda for after they left. After they left I want to my favorite open cluster NGC 2362. It has been a couple of years since I have sketched this and so I decided to sketch it. I am going to post my sketch here but I will re-post it as I took out the glare I had tried to put in and just put Tau back in. I like it better like that. Here is Tau Canis Majoris or NGC 2362.  You can see my other sketches of this cluster at this link.


After I got done with sketching NGC 2362 I went back to NGC 2392 or the Eskimo Nebula and sketched. Man, I can tell I am out of practice with sketching! I like the color (I used color pastels here) and I got parts of the outer shell captured well but the inner ring is too wide.  Now I have something else to work on again. Man, I hate the weather which makes it impossible to observe. Go figure, the last 3 nights including tonight have been clear and wonderful. The issue is the waxing crescent moon that continues to throw light up. I guess I should set up around 12:00 a.m. and observe from 1:00a.m. to dawn to do spring objects. I am so out of shape in observing and sketching . . . All I can say is I have really hated the last 3 plus months in terms of the sky.

NGC 2392 The Eskimo Nebula or PN in Gemni.



The last object that I was able to get was NGC 2217 a Spiral Galaxy in Canis Major.  The central region and core of this galaxy is oval shape and very evident in the eyepiece. Man, I blew the oval shape on this one so back to practicing I guess. I also with the wonderful contrast of my 14 inch Zambuto mirror was able to grasp what I felt were a couple of wisps on the brighter part of the outer ring of this galaxy.  I tied to capture that in sketch.



 So there you have it. A fun night, a good night, and one where I got to practice sketching from the right side since I moved my focuser and finders to that side since I am left eye dominant.  That and not sketching for 3 months made me rusty in terms of sketching and I rushed which I feel is reflected in my sketches.  So there you have it. Glad I got some time in even if the moon was up. Oh yeah, we looked at the moon also. Perhaps its time for me to really start sketching the moon since it is so clear when it is up; well at least until Wednesday when the next major snow store arrives.

2/14/2013

Eyepieces and Which Wide Field: 24mm Explore Scientific 82 degree vs 27mm Pantoptic 68 degrees


   27mm TeleVue Panoptic or 24mm Explore Scientific 82 degree as a 2" finder eyepiece




  For some time now I have been using the 27mm Panoptic as my finder eyepiece in my 14 inch dob.  The 27mm Panoptic offers a good dark background, solid magnification of 61x in my 14" dob with a field of view of 1.11 degrees and a 19mm eye relief. It weighs 18 ox or 1 lb 2 oz.

Over the holidays Explore Scientific had their promotion going on where they sent a piece of the asteroid Campo del Cielo from Argentina with a ten percent discount.  So I ordered the 24mm Explore Scientific 82 degree eyepiece. I had heard many wonderful things about this eyepiece and I wanted to try out my wide field experience.  This 2 inch eyepiece weighs in at 1 lb 6 oz. (4 oz. more than the 27mm Panoptic).  The listed eye relief is 17mm and it seems to be close, about 16.5mm as I reckon. This eyepiece gives a magnification of 69x and a field of view of 1.19 degrees.

So now I'll compare the stats of these two eyepieces.

                    TeleVue 27mm Panoptic 68 degrees                                 24mm Explore Scientific 82 degrees

Field of View                 1.11 degrees                                                                 1.19 degrees

Eye Relief                       19mm                                                                             16.5mm

Weight                             1 lb 2 oz                                                                      1 lb 6 oz.

Magnification                     61x                                                                             69x

To see how the eyepieces show a field of view I used Starry Night Pro to show the differences.  Here are some of those images.


Here is Messier 95 & 96 and Messier 105 in the same field of view. In all of these images, the green will be the TeleVue 27mm Panoptic and the 24mm Explore Scientific 82 degree is the yellow.  It is easy to see that the ES 24mm gives the better overall field of view here.


Here you can see the field of view for the Leo Triplet, Messier 65, 66 and NGC 3628 in Leo.  Again, all three objects are in the field of view of both eyepieces, with the 24mm Explore Scientific giving a wider field of view.

Well, I wanted to show Messier 42 and the Double Cluster but my program isn't saving correctly. So I'll have to use the two images above.  In trying to decide which eyepiece will be my finder eyepiece, I have several things to consider. First, my 14 inch dob can get top heavy and though balanced to work with a Paracorr, a 30mm ES 82 degree eyepiece, a 9x50 finder and a Telrad, I prefer not to run that much weight too often. So with weight being a concern, the Panoptic has the edge so far. Next if I look at the actual field of view and can see that for the most part, the slightly larger field of view of the 24mm ES 82 degree isn't enough to really over come the field of view of the 27mm Panoptic.  So with weight going to the 27mm Panoptic, I looked at other factors. The 24mm ES 82 degree has a lot of coma without the Paracorr in.  The coma is a good 30 percent out from the edge.  The Paracorr cleans it up but with the 27mm Panoptic coma is not really an issue with the Paracorr and the pincushion issue is resolved for me.  Edge here goes to the 27mm Panoptic.  Magnification is relatively close so that isn't an issue, and I like the lower power of the Panoptic 27mm.  Last is eye relief.  I do wear glasses and though my astigmatism isn't bad, and I can observe easily without my glasses, I usually leave them on as I need them to look at constellations and align the Telrad.  So here the Explore Scientific has a 16.5mm eye relief vs the 19mm of the 27mm Panoptic. Edge for me has to go to the Panoptic.

So in weighing these factors my final decision is that the 27mm Panoptic will remain my wide field eyepiece of choice. I like the 24mm Explore Scientific 82 degree and to be quite honest for the $179.99 I paid made it an excellent choice for someone who cannot afford the $370.00 for the 27mm Panoptic.  Now I need to come to a decision on what to do with the 24mm Explore Scientific 82 degree eyepiece. Do I sell it for my cost of $179.99, which is cheaper than the cost of a current new one? Do I hold on to it and use it from time to time in my 10 inch dob? I'll probably keep it for awhile and use it for outreach and for in case an observing friend needs a wide field eyepiece to use.  I may end up selling the eyepiece in the next couple of months on Astromart or on CloudyNights.

I hope someone benefits from how I went about evaluating the two eyepieces from the field to here. I wouldn't lose using either eyepiece and so in the end, if I didn't own the 27mm Panoptic and hadn't purchased it for $270.00 new a couple of years ago, I would be just as happy with the 24mm Explore Scientific 82 degree eyepieces.

I did some more comparisons to ensure I have what I want.  Here is the chart I put together using my 1650mm 14 inch dob.

Cost                  EP                  ER                   Mag                 FOV                         Weight
$299.99         ES 20mm 100    14.5mm          83x                     1.21 degree              2lbs 2oz

$199.99         ES 24mm 82      17mm             69x                      1.19 degree              1lb 6oz

$29.99         ES 30mm 82       21mm            55x                       1.49 degree              2lbs 2oz

 $119.00        ES 24mm 68      18mm            69x                       0.99 degree               11.2 oz

$99.00            ES 20mm 68       15mm           83x                        0.82 degree              8.8 oz

$370.00        27mm TV Panoptic   16mm        61x                        1.11 degree              1lb 2oz

I did this an experiment to see if I have really found my wide field eyepieces. This may sound crazy as I spend money for land to observe on, spend money on a premium mirror etc. but I would prefer not to spend $600.00 to $1000.00 per eyepiece for TeleVue's.  So what does the table show me? Yes, I have the eyepieces I need. I was thinking of the 20mm ES 100 degree EP again but decided not to. The 24mm ES 82 degree and the 27mm TV Panoptic will work for me.  I put the 24mm 68 degree to compare it to the 24mm ES 82 degree I have and no, that is not the eyepiece I want.  I'm happy with what I have.

2/10/2013

Sketches and Sketching Mask NGC 1365, Rosette Nebula, IC 443

Over at CloudyNights a couple of weeks ago, the question was asked about using what I call the "Circle of Death" which is the ring that many sketchers put around their sketch to stimulate the field stop seen in the eyepiece. I use to use the field circle but when I moved to the Mellish method a couple of years ago I gave up the field circle. For me the field circle limits my sketch.  It does serve a purpose of keeping perspective and accuracy in a sketch, though I believe you can maintain that without keeping the field circle in the sketch. There are two ways to accomplish this. One is to simply keep the field of view as you sketch, and include it in the sketch.  The other thing is to create a mask that has the circle and you use masking tape to put it in place over the sketching paper and sketch within the circle. Here is what I posted on CloudyNights on why I don't use the circle. 

  First the Circle of Death I have found limits me as a sketcher. Scale is important, and yes, I try to keep scale, but with that circle in place I find I am more worried about the circle than about actually sketching and thus the sketching suffers. For a new sketcher learning techniques, I think they need to focus more on technique and mastering them rather than on perfect accuracy. The reality is of the couple of thousands of sketches I've made, most are for my enjoyment and to show me that I have actually improved in my sketching efforts. 

I also find that even a thin line impacts the view of the sketch. I simply think the sketch looks better without the border. I did make my mask and will be posting it on my blog in the next several days. In addition I am going to make a couple of practice sketches with it to see if I like it.

Finally, this is my opinion. I think there are two views of sketching. One is where the sketcher really, really wants to be accurate for a study or some other project. Then a circle or a mask can be very helpful. You can see this in this link to Stephen Waldee's article on sketching the horsehead that I did (near the bottom). Here the circle helped me to create an accurate sketch. The other view is where a sketcher wants to capture an object, an observation and wants to objects to close in accuracy but it doesn't have to be perfect or even close. Here a sketcher doesn't have to use a circle and can focus on sketching and on the sketch itself. Often that leads to a greater enjoyment of the process. Sketches for contests, sketches for articles and such need to be as accurate as possible. Sketches to record an observation, an experience, a point at time at the telescope can be accurate, but often it is the experience that matters most. I do both and enjoy doing both and I personally believe if one really tries, without a border circle, one can still be really close in accuracy and it leads to a better view. As I mention, if I sketch without the border, I don't really notice the field stop and I focus on the object I am sketching and keeping it centered and for me, and only for me, I enjoy that experience a LOT more. I hope I answered your question while providing options for others to decide which way they like to sketch. I don't think there is a right way or a wrong way, there is a way that works for the sketcher.

My personal goal if this two and a half month weather pattern of clouds will ever clear up is to go after a few well known objects and then on my blog I'll post a comparison of true field of view and alignment of stars and of the object without a mask or border. I think that will be a very interesting study to do and I have to thank you for the idea. 

I haven't had time to go out and do a comparison of true field of view and stop and alignment of stars and of the object with a mask and without a mask.  So, the following 3 sketches are sketches I made of the following objects, NGC 1365, a barred spiral in Eridanus, the Rosette Nebula or NGC 2237, NGC 2238, NGC 2239, NGC 224 and NGC 2246, and IC 443.  I've sketched two of the three before but this time I felt that the contrast of the Zambuto mirror was so much better that the UHC and OIII filter really stuck these items out.  

I used my 10mm and 7mm Pentax XW on NGC 1365, the 30mm ES 82 degree, the 27mm Panoptic and the 20mm ES 60 degree on IC 443 (with UHC and OIII 2 inch or 1 1/4 filters), and the 24mm ES 82 degree, the 27mm Panoptic and the 30mm ES 82 degree with the two filters for NGC 2237 the Rosette Nebula.  In sketching them I used a mask so you can determine if you like the mask or not to reflect the field stop.  Oh, that is another point. I often on larger objects will use at least 2 eyepieces to capture the sketch and I find the field stop circle of death prohibits the view I am trying to capture.  Anyway, here are the sketches.


NGC 1365 Barred Spiral Galaxy in Eridanus: 






IC 443 Supernova Remnant in Gemini:




NGC 2237 Rosette Nebula



2/09/2013

Updates to my 14" Dobstuff with 14 inch Zambuto

Well, tomorrow I am going to upload my sketches and post them. Last Saturday I and a few friends, Mat, Jeff, Josh and a new friend and a friend of Jeff went to the Pit n Pole location (for the last time during the fall, winter or early spring).  Our equipment frosted up and you can see that on my friend's Mat mirror after he got home (he left the mirror uncovered on the drive home and it still frosted right up!).


So, until summer when that site doesn't have any dew issues, we won't be returning there.  There are some other sites that are closer and don't have this problem so if we want a close site, we will be going there.  That observing night for me was 2 hours of getting the scope set up, and remembering what worked and what didn't.  I found that night I really had a balance issue for the scope.  So today, I took the scope over to Mat's house for an ATM session and we worked on the balance issues and a few more things.

One of the things I've noticed when using my new Dobstuff 14" Dob, is that at Zenith it was just a little taller than I am (I'm 6 foot) so I had to get on my tippy toes in order to view. Since the scope has a balance issue with too much weight on the upper OTA, and I wanted to lower it a little, today we drew two new identical holes where the bearings are connected to the mirror cell.  Here is a picture.


This hold had a slight split that I have since filed in and will cover with stain so it matches the wood.  This had an amazing affect on the balance of the scope, giving a really good new center of balance. After this Mat put on some counter weight with magnets and large washers strewn together and for the vast majority of travel in azimuth the scope was great. Down low and up near zenith the scope was still out of balance. This was with a Telrad, a 9x50 RACI, a Paracorr Type 1 with the white lettering, and a 30mm Explore Scientific 82 degree eyepiece in the Moonlight focuser.  This is the heaviest set up I would ever use.  At this point we had  put a 1 1/4 lb round weight on that right foot and held in place for now by the rubber foot that fits snug there.  The result was using that and then using the adjustable sliding counter weight on the far left strut, we achieve a perfect balance for the above set up and for any combination of my eyepieces. We tried the TeleVue 27mm Panoptic, the Pentax XW eyepieces and all worked wonderfully.  This means that any eyepiece I have in my collection will work with the Paracorr Type I on this scope with the scope being balanced from down low to zenith.  YES!!!!! Thanks Mat, Josh and Jeff for your help on this. We also put the Telrad and the 9x50 Finder together on the same Strut and this combination worked extremely well.  I'll post a picture next time I put the scope together.

One item I found well checking the balance is that the Formica on the bearings were connected with a tack, but they weren't glued down with contact cement. My friend Mat made his 16 inch dob 15 years ago and he glued and tacked his Formica down and after 8 plus years he removed the tacks as the glued Formica hasn't come loose at all.  When the weather warms here in April we will glue the Formica down on my dob as well.   This will stop the small popping sound I get as I move the scope up and down in azimuth.

Once this was done, we also moved the front Teflon on the bearings up so that the azimuth and altitude motions matched.  This was the final adaptation we did to the scope.  At this time the scope is in balance and the motions which are buttery smooth, matching in their silky smoothness (azimuth was probably just a touch too smooth vs altitude). Here you can see the Teflon that we moved forward, and the former hole.





If you get a DobStuff Dob and like me, you get the String Telescope version to hold your collimation, you'll find that the end of the strings are sharp and very pokey.  I LOVE the strings and how they help to keep the scope in collimation. I don't like how the ends begin to fray and the wires stab me as I attach them to the scope. So we found today a very simple fix.  Mat in his shop/garage where we do our ATMing also bikes (he is an avid biker) and had a slew of brake kimps that are used on bikes to krimp down the braking wires so they don't flay and stab.  So after Josh and Mat had put the ends back together they were able to put the ends into the brake kimps and after krimping them, the ends are fixed and no longer will stab me or anyone helping me put the strings on.  Here's a picture of the ends put inside the brake kimp before being krimped.




Here are both ends after being put in and krimped down.  YES! No more stabbing (it really does hurt!).



So since its new moon, snowing the state of Utah and cloudy in the entire state, instead of observing, my scope is now up and running and I won't need to spend time in the field setting up and adjusting.  I love my scope and like any new scope, it needed a few tweeks which are now done.