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First Light On My 20" f/3 Lockwood/JP Astrocraft

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#126 a__l

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Posted 06 January 2013 - 01:44 AM

Bob, but for what you have cleaned the glass SIPS? F/3.0 coma and big enough for Mallincam (probably?). Incompatibility SIPS and Mallincam?
I would be very interested to read the result of using SIPS (complete) + Mallincam + yes/no FR ...

#127 Busguy

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Posted 06 January 2013 - 02:38 PM

I'm also anxious to hear the answers on the SIPS + Mallincam and how you achieve final focus.

#128 a__l

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Posted 07 January 2013 - 07:25 PM

I asked an additional question in the subject Video and Electronically Assisted Astronomy:

I want to determine the position of the focus for Mallincam.
The focuser on my Dob set to eyepieces Ethos-17,21 and Nagler-31.
Here
http://www.televue.c...page.asp?id=214

Eyepiece Specifications for TV eyepieces.
Table Notes F - Approx. location of field stop (negative number is above reference surface).
For E-21, 17 and N-31, respectively -0.38, -0.39 and -0.38.
This is the minimum benchmark. Below focuser travel impossible.
If you remove the Mallincam (focus OK) and set TV eyepiece. Which TV eyepiece is in focus (does not need to turn the knob focuser)? Or near the to the focus?
If you are using a 1.25/2" adapter for Mallincam or desired TV eyepiece I also need an height adapter on above surface focuser.
If the TV eyepiece is 1.25/2" skirt, it is correct to use a 2" eyepiece position.
Thanks.

#129 Bob S.

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Posted 09 January 2013 - 10:25 PM

A___I and Busguy, I was finally able to plug in my Mallincam Xtreme with the 1.25" nosepiece and a 10mm spacer with my SIPS in place and the camera came to focus on M42. I only had about 1/4" of out-travel available but it worked! I was frankly a bit astonished.

Tonight, even though the weather has been terrible in North Florida and was pretty lousy all day, the seeing was very steady at times and I was able to use 373x and 474x on Jupiter with the CBLMS (Comprehensive Boundary Layer Mitigation System) running. The best views were at 373x with my 4.7mm Ethos. The GRS and following white ovals were prominent at times. The long blue festoons in the NEB were also pretty apparent and I am scheduled to get cataract surgery which will greatly increase my blue sensitivity. I was suppose to have the right eye done today but am getting over the flu and was in no condition to get eye surgery. Wasn't even in good enough shape to work more than about 2 hours today but when it came to astronomy, I was so photon starved that I was out for more than 2 hours tonight. I guess my priorities are still good :shrug: Bob

#130 a__l

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Posted 11 January 2013 - 07:13 AM

A___I and Busguy, I was finally able to plug in my Mallincam Xtreme with the 1.25" nosepiece and a 10mm spacer with my SIPS in place and the camera came to focus on M42. I only had about 1/4" of out-travel available but it worked! I was frankly a bit astonished.


Bob, I'm glad that it worked!
I do not understand the nuances.
1. SIPS was set with a view to focus Ethos 17 and focuser with a maximum travel inside?
2. You have used 1.25/2" adapter (with Mallincam)? What is the height this adapter above plane focuser?
3. What is a 10mm spacer? Where it is set?
4. Height focus Mallincam 1/4" (travel focuser 1/4" outside of focus from the ethos 17)?
If you can, please place the a picture with dimensions.
Thanks.

#131 Sgt

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Posted 11 January 2013 - 04:19 PM

Bob, sorry if I missed it but can you give an assessment of the Leica zoom on and off axis at f/3+paracorr? Thanks.

#132 Bob S.

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Posted 11 January 2013 - 04:28 PM

Bob, sorry if I missed it but can you give an assessment of the Leica zoom on and off axis at f/3+paracorr? Thanks.


SGT, I will let you know. I will be using it with my SIPS system and will let you know how tight the stars are and how tight they are out to the edge of the field.

#133 Sgt

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Posted 11 January 2013 - 05:50 PM

Thanks Bob.

#134 Bob S.

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Posted 11 January 2013 - 09:34 PM

SGT, It is too early in the evening to tell about my early exploits but I can tell you that the Leica ASPH is currently in my 20" scope in a 4x TV Powermate and the views of Jupiter, M42, and the Eskimo Planetary Nebula between 389x and 777x are pretty darn wild. The 2x Powermate that was limiting me to 389x was just not enough power for tonight. Finally, I get to really air this scope out! Bob

#135 Bob S.

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Posted 12 January 2013 - 12:47 AM

The coyotes were literally howling, the owls were hooting and a Leica ASPH vario zoom 8.9-17.8mm with 60-80 degree AFOV got an intense workout tonight in my 20" f/3 Lockwood/JP Astrocraft. The NELM was just under mag 6 tonight as measured by my Sky Quality Meter and the seeing was quite steady. Earlier experiments tonight with the fans on Jupiter and Rigel showed that the (Comprehensive Boundary Layer Mitigation System) is working superbly. I tuned the SIPS to perfection on Jupiter using a 5x magnifying loupe and checked collimation of the scope after it had been cooling with the CBLMS running at full speed for about 1.5 hours. I was looking at Jupiter with the Leica ASPH and was finding that 194x was not even making the eyepiece or the scope breathe deeply. I popped the Leica ASPH into my 2x TV powermate and now was running views of the planet between 194x-389x. Still the views were showing that I could use more power. In goes the 4x TV Powermate coupled to the Leica ASPH for views between 389x-777x. Predominantly, the views at about 389x to about 600x showed periods where the planet looked like a CCD image. The orb of Jupiter seemed suspended in black space. The contrast of atmospheric features against a jet black background was jaw dropping. Now, for the first time since this past years WSP in the Florida Keys, I was able to view comfortably at over 550x. With the ASPH in the 4x Powermate and a 2" OIII filter, I had the scope go over to the Eskimo Planetary Nebula in Gemini which is an object on good nights that can take a lot of power. The Eskimo was not to disappoint either then or hours later at ridiculously high mags. I am used to viewing it with my former 28" f/3.5 Lockwood/Starmaster and so noticed that the brightness was way down with the OIII filter and only 20" of aperture compared to the views I would get with the 28". Now, I had not had a chance to see the Horsehead and Flame Nebulas with my new scope. I put a 2" H-Beta filter into the bottom of my ASPH and was zooming in and out on the Horsehead and Flame Nebulas. I actually like the view better in my Leica at 17.8mm with 60 degree AFOV than my 21mm Ethos or 17mm Ethos with the h-b filter and their 100 degree AFOV.

Of course, in the high mag mode, I had to see the Pup in Sirius. Sirius was a superb pinpoint of a star and I used it for further high-mag testing of the primary mirror. I did a test of the fans on this object and each time I turned off the CBLMS, the star would get more flairs. The tightest views were with the CBLMS running and so it was left on all night. Back to Jupiter with the 389x-777x eyepiece arrangement and Jupiter was strutting the GRS along with beautiful festoons and white ovals and a dark barge or two in the NEB. The amount of different colors I was seeing in the GRS, festoons, ovals, barges and belts was very impressive. At between 550x-777x, I was able to make out reliable but faint albedo markings on Ganymede in what I think was the Southern half of the Jovian Moon. This is only the third time that I have been able to do that and it was best seen when I moved Jupiter out of the FOV. I forgot to mention that I used the ASPH with the 4x Powermate on M42 and was seeing the A-I stars (not the H-stars). The G and I stars were only intermittently seen with averted vision. This is only the second time that I have seen the I and G stars without my image intensifying eyepiece. BTW, I tried my Micro IIE Gen 3 image intensifier and was unable to get it to come to focus with the SIPS system in place. I was lacking just a bit of infocus. I finished off the session tonight first returning to the Eskimo and seeing his face briefly with a full parka surrounding his face and nose. I then went back for a last look at Jupiter and the seeing was getting a bit soft even at a lowly 389x. It was time to wrap it up and glow in the aftermath of my best viewing session to date with my new telescope. It also represented the best magnification I was able to successfully deploy in the past year here in North Florida. For some reason, obtaining 1000x plus nights like we used to get have been very difficult for the past two years. I did some high-power testing of the mirror on Sirius and Betelgeuse and the mirror is superb! Mike, I found that the Leica showed pinpoint stars to the edge with tighter star points when it was in either the 2x or 4x Powermates with those items behind the SIPS. Without a barlow, the stars were a bit less tight and not so uniform across the FOV with just the Leica ASPH and the SIPS. The views were not bad but just not perfect like they were with barlowing. I am including a picture of the setup. You will note that all focusing was done with my 3" Feathertouch optional focuser wheel which made focusing a dream. I cannot say enough good things about this 3" focuser wheel for critical focusing at high-mags. To say that I am pleased with the scope and the performance of the Leica ASPH with the TV Powermates would be an incredible understatement. I am frankly ecstatic! I am very much questioning if I need all of my fine Ethos ep's (I have the whole set). As some know, I had done comparisons of the Leica ASPH with my Zeiss Abbe Ortho II's along with a host of other orthos and ep's and the Leica was a good as or at times better than the Zeiss glass and this is no small accomplishment. It's performance on Jupiter was so convincing tonight and the fact that it was being used in a f/3 scope with a Starlight Instruments Paracorr System (SIPS) that made the AFOV perform like an f/12 scope leads me to wonder how much glass I need? I am forever indebted to John Pratte for making such a stout scope with an ultra-stout focuser board/UTA that easily handled all of the weight placed on it. This is without a doubt, the finest 20" scope I have ever been priviledged to be the steward of. Bob

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#136 Mike Lockwood

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Posted 12 January 2013 - 12:20 PM

Bob, all I can say is wow.

Things have sure come a long way since I bought these 20" f/3, 1.25"-thick Pyrex blanks back in 2006. I could never have forseen what they have become.

Thanks for your report, and for trying a lot of things that most people would not.

#137 claytonjandl11

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Posted 12 January 2013 - 02:11 PM

Very nice report Bob, keep them coming.

There are times that miss the views from a large apeture scope. I remenice when I had my 20" SM and would scan the the night sky and I kept bumping into these obscure little galaxies, and I'd check my sky atlas to see what I was seeing. Not to mention how different and in your face the "eye candy" DSO looked compared to my smaller apeture Apo's, just one word, WOW!!!

The only thing I don't miss is the size and weight of that scope, and the hassel of using a ladder, setting it up and tearing it down. But not in your case, with the fast F/ratio keeping yor feet on the ground and those superb optics and the abilty to customize your scope. Between your posts and advise, and looking thru some of my freinds large apeture, fast F/ratio with top of the line optics like yours, and the lighter overall weight and portabilty of these scopes have made me belive in these type of reflectors. For me it has always been a case wanting the sharpest veiws with ease of use and portabilty. In other words "The juice had better be worth the squeeze". In this case you and others like yourself have proven this. I can't wait to get my 16" Spica Eyes scope!!

Nick T. :-)

#138 SACK

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Posted 12 January 2013 - 02:58 PM

Hi Bob,
How does the 5X loupe help you for sips adjustment? How do you use it and are there other uses, i.e. collimation? Sounds intriguing.
Thanks for the ongoing reports and insights!
Jonathan

#139 Project Galileo

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Posted 12 January 2013 - 03:44 PM

Congratulations on the fine results. You have a special telescope there my friend.

#140 Bob S.

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Posted 12 January 2013 - 04:06 PM

Hi Bob,
How does the 5X loupe help you for sips adjustment? How do you use it and are there other uses, i.e. collimation? Sounds intriguing.
Thanks for the ongoing reports and insights!
Jonathan


Thanks for the kind words Mike, Nick and Doc. Jonathan, the 5x loupe is a large magnifying glass that I used to increase the image size of Jupiter on the SIPS cellophane tape method to determine when the SIPS was resolving the object perfectly at the focal plane. By using an image magnifier, I can better discriminate the focus on the tape and when the SIPS is tuned to the correct position to provide optimum coma correction for the eyepieces. If you look at the image on the cellophane without magnification, I think it is harder to discriminate when the SIPS is turned in/out just the right amount. When I find that perfect focus point, I then can lock in the SIPS and then check to see that I have not drifted off that perfect spot. It usually takes a time or two to properly tighten the SIPS without degrading the image just a touch because you are dealing with a tightening ring and also rotation of the focuser to lock it in place. As Fast Mike pointed out, he can then use his 17mm Ethos to establish where the best focus is with the eyepiece projecting the target instead of the cellophane tape on the SIPS adapter tool. I measured the distance from the back of the SIPS lens to the edge of my SIPS focusing tool and it was exactly 55mm for my scope. From now on, I can just use that figure to set the distance and not worry about any of the other shenanigans. Simplicity is why I bought the SIPS and I do not want to have to be fiddling with it very often. Bob

#141 Busguy

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Posted 12 January 2013 - 04:36 PM

Bob, I would also like to add my thanks for your reports. I imagine I will need hands on with my own scope to sort out Mallincam. That's the joyful experimentation. First I need to take delivery of the telescope. Been a long wait.
Look forward to further reports.

#142 Sgt

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Posted 12 January 2013 - 05:14 PM

Thanks for the report Bob!

#143 a__l

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Posted 12 January 2013 - 06:27 PM

I measured the distance from the back of the SIPS lens to the edge of my SIPS focusing tool and it was exactly 55mm for my scope. From now on, I can just use that figure to set the distance and not worry about any of the other shenanigans. Simplicity is why I bought the SIPS and I do not want to have to be fiddling with it very often. Bob


Bob, an additional question. In this position SIPS, you adjust the focus with the Ethos-17?

#144 Bob S.

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Posted 12 January 2013 - 06:52 PM


I measured the distance from the back of the SIPS lens to the edge of my SIPS focusing tool and it was exactly 55mm for my scope. From now on, I can just use that figure to set the distance and not worry about any of the other shenanigans. Simplicity is why I bought the SIPS and I do not want to have to be fiddling with it very often. Bob


Bob, an additional question. In this position SIPS, you adjust the focus with the Ethos-17?


No at 55mm out, the SIPS is properly focused for my telescope. The 17mm can then be a reference for where it comes to focus best. It is takes about 1/2 turn of the fine focuser to get it to come to focus for Fast Mike's scope. I am not exactly sure with the arbitrary 55mm that mine is out how much more outfocus the 17mm Ethos will demand to come to focus? Bob

#145 Bob S.

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Posted 12 January 2013 - 07:08 PM

A very interesting topic of conversation came up on the Yahoo Lockwood Mirror site concerning my temperature management system dubbed a CBLMS (Comprehensive Boundary Layer Mitigation System). Mike Lockwood advised that for many years he has noticed that the sea breezes at the Winter Star Party in the Florida Keys seems to help many of the Newtonians to perform at higher levels than might be expected elsewhere. Mike suggested that the ability to cool the mirror from all sides that the sea breezes provide may be a large factor in mitigating other temperature-related variables such as body temp, ground temperature, scope materials that may be deleterious to the microcosm of an environment just above the surface of the primary mirror. Lockwood advised that his 20" f/3 that is also 1.25" thick seems to perform better when the breezes kick up a bit at his prarie location. He does not have fans on his 20" f/3 Starmaster and appears to have noticed beneficial effects from the entire mirror being bathed in constant temp air. I hadn't thought this completely through before but I suspected that ground heat and certainly body heat could affect the seeing environment inside our Newtonian telescopes. Daniel Mounsey has been a very strong advocate for the degradation caused by scope positioned down wind from our hot bodies. It also makes great sense to me that head radiating from below the scope would not benefit seeing and that is why scopes set up on cool grass as opposed to hot concrete/asphalt seem to perform better. Wow! This is an interesting turn of events. From my early data, there seems to be little doubt that the CBLMS is additive and much more so with both fans running simultaneously. Bob

#146 a__l

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Posted 12 January 2013 - 07:09 PM

Bob, I would also like to add my thanks for your reports. I imagine I will need hands on with my own scope to sort out Mallincam. That's the joyful experimentation. First I need to take delivery of the telescope. Been a long wait.
Look forward to further reports.


If I understand correctly, the spare travel for Mallicam is 6 mm (with unknown settings SIPS).
Further, an additional limit of 10 mm height spacer + 1.25/2" adapter (height not known). It is not known whether the set HDX2-F kit (camera XTREME), the limit may be higher.
If replacement mode 1.25 to 2" (new 2" Focuser Dob Adapter for Mallincam - $ 89.99) get spare travel 10+6+(?) mm (minimal).
Since the field Mallincam little, there is a chance to try MFR-3+10 mm spacer (travel 14 mm).
But! All these issues need to be clarified with the manufacturer Mallincam.

#147 Mike Lockwood

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Posted 13 January 2013 - 11:07 PM

In comment to Bob's most recent post, what is important here is that now the conditions are present/satisfied that allow very fine differences in performance to be discriminated.

With 1) good optics, 2) good mirror support (edge and back), 3) good collimation, and 4) good equilibration made possible by the fans and thin mirror, the scope is performing up to the potential of a quality 20" visual instrument.

The conventional technique of blowing air on the back of mirror will help for a while, but it causes an uneven temperature distribution in the mirror and eventually when the mirror does cool it starts pulling the warm air off the ground back up into the mirror box. The cooling system in the 20" f/3 avoids that, and cools all sides of the mirror much more evenly, something that I have recommended for years to those that have asked me. Even cooling is vital for the ultimate performance on most nights. While one may get lucky with conditions on a few nights a year, with a cooling system like this there are going to be a lot more of those amazing nights.

#148 Bob S.

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Posted 18 January 2013 - 10:32 PM

Finally, Even with seeing being 5/10 (Jupiter was boiling even at low mag) and a half moon about 35 degrees away from the Horsehead Nebula, I was able to finally deploy my Mallincam Xtreme connected to my integrated laptop computer in the 20" f/3 Lockwood/JP Astrocraft telescope. I was able to get very good images up to 65 second exposures which is unreal! I am including a screen shot of the control center values for the Mallincam and then an unretouched photo of the Horsehead nebula displayed on my 3.5" Watec monitor with a 55 second integration.

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#149 Bob S.

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Posted 18 January 2013 - 10:34 PM

Here is my poor photo of the Watec monitor and a 55 second integration on the Mallincam. I was able to use the MFR-3 and a 5mm spacer and was able to keep the SIPS system in place. I had to rotate the SIPS system in about 4 complete rotations to get the Mallincam to come to focus with a little infocus left (about 1/2 turn of the fine focuser knob on the Feathertouch). BTW, I left the Comprehensive Boundary Layer Mitigation System on at their lowest speeds and the fans being on another circuit did not seem to affect the Mallincam images on the monitor.

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#150 Bob S.

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Posted 19 January 2013 - 07:32 AM

Here is a closeup of the Mallincam Xtreme in the focuser and you can faintly see the Horsehead Nebula on the Watec screen with my handheld camera's flash wiping out most of the percept you are seeing (you can see the star field and better image without the flash in the post just above this one). The extra dangling cable is a connnector for a Baluns that would allow S-video output that is remotely located on the side of the mirror box that can then run out to a larger monitor or be the terminus for a wireless transmitter. Those features will be utilized further down the line. I am absolutely delighted that another proof of the concepts we integrated into the scope are bearing fruit. As many of you ATM'ers know, you do your exhaustive homework, think and re-think all of the various components and then roll the dice. I also need to do a serious shout out to Gary Myers of ServoCat for producing a drive system that has allowed me to get round stars on the Mallincam with 65 second integrations. I am not sure what the upper limits are yet on the whole system? Thankfully, we did not roll "snake eyes" last evening :lol:

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