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Tips for a soon-to-be 25" Obsession Owner?

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#26 CHASLX200

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Posted 20 January 2020 - 06:35 AM

 

To address Tommm's comments:

 

A 2004 Nissan Frontier:

 

 
 
A Ford Transit Van:
 
 
 
 
 
 
 
Jon

 

It's not fitting in my Vette.



#27 Dougeo

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Posted 24 January 2020 - 07:13 AM

I spend most of my time in LA for school, so the scope will be going back to my home in Arizona, but unfortunately I live in the suburbs of Phoenix (Bortle 8-9). I'm within an hour of great, dark skies but I don't doubt that transportation and assembly is very fun at all so I'm a little torn on what to do.

Well now that you have had excellent advice and time to think what is your decision, to get it or not?



#28 Yogurthawk

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Posted 24 January 2020 - 11:29 PM

Well now that you have had excellent advice and time to think what is your decision, to get it or not?

I can't really go through the details of it online, but I will be receiving the scope for free, essentially. For me it's a no brainer to try and give the scope a good home where it can get some use, so I'm currently in the process of figuring out the logistics of transporting the scope. I think I'm going to try and drive out to nearby dark sky spots and set it up in the field. If that proves to be too much work I'm going to look into ways to get it stored permanently at a dark spot.

 

I really appreciate all of the great advice you guys have given me, though. I will surely use many of the tips posted.


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#29 Dougeo

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Posted 25 January 2020 - 01:28 AM

I can't really go through the details of it online, but I will be receiving the scope for free, essentially. For me it's a no brainer to try and give the scope a good home where it can get some use, so I'm currently in the process of figuring out the logistics of transporting the scope. I think I'm going to try and drive out to nearby dark sky spots and set it up in the field. If that proves to be too much work I'm going to look into ways to get it stored permanently at a dark spot.

 

I really appreciate all of the great advice you guys have given me, though. I will surely use many of the tips posted.

A sweet deal for sure, I would do the same thing and have fun making it work outwaytogo.gif

Once you get your logistics figured out I invite you to set it up at my place as a test run to see how it goes. I’m in the far east valley at the base of the Superstition Mountains in fairly dark skies.



#30 Yogurthawk

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Posted 25 January 2020 - 08:26 PM

A sweet deal for sure, I would do the same thing and have fun making it work outwaytogo.gif

Once you get your logistics figured out I invite you to set it up at my place as a test run to see how it goes. I’m in the far east valley at the base of the Superstition Mountains in fairly dark skies.

That would be awesome. I might send you a message later on then. Thanks!



#31 sn1987a

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Posted 26 January 2020 - 05:25 AM

Here's a video of me setting up my 28" a scope similar to your 25". I carry it in a dedicated cheap secondhand ramp rear door trailer I bought. 12 minutes to set up from arrival on site. You'll probably be wary of my ladder solution though! tongue2.gif

 

https://www.youtube....iotbD-ZA&t=182s

 

 

 

 

 

 

Cheers

 



#32 a__l

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Posted 26 January 2020 - 05:51 AM

Here's a video of me setting up my 28" a scope similar to your 25". I carry it in a dedicated cheap secondhand ramp rear door trailer I bought. 12 minutes to set up from arrival on site. You'll probably be wary of my ladder solution though! tongue2.gif

 

The rag bag on the secondary mirror is best replaced with something that does not absorb sharp dust.

Who put the filters on the encoders? Webster?



#33 Dougeo

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Posted 26 January 2020 - 07:40 AM

That would be awesome. I might send you a message later on then. Thanks!

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#34 sn1987a

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Posted 26 January 2020 - 08:27 AM

The rag bag on the secondary mirror is best replaced with something that does not absorb sharp dust.

Who put the filters on the encoders? Webster?

The encoders there are an optional 30k upgrade from ServoCat I purchased replacing the original 10k ones that Webster fitted. After the new encoders went on I had issues with interference and Gary suggested the filters which worked. The bag is a calico mining sample bag I bought a box of them at auction years ago for 2$. I've had the bag on the secondary for 7 years now I hadn't really noticed or considered any issues with dust. If it gets dirty I either wash it or replace it. I think Dave Kreige uses a sock doesn't he?. 



#35 a__l

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Posted 26 January 2020 - 05:52 PM

Yes it is. I read about it. But I read from users about the fact that it scratches the surface of the secondary in small stripes.

 

By 10K encoders. The noise is still 10K or 30K. Feature of ArgoNavis+ServoCat. At 10K it's fewer failed events. Eliminated by isolated ArgoNavis power supply (e.g. lithium battery).

 

By installation time. It is necessary to add a power connection, check the operation of the secondary heater, motors and encoders (contacts!), and troubleshoot, if any. Further collimation. Pulling a shroud. Finder setting. Placing the telescope at its zenith. Fixing.  Alignment on two stars. In total, this will increase the time by two to three times.

 

Ps These are small refinements. Large telescope is a large telescope. I like the design of Webster. But I would still prefer without a ladder. With reasonable faster. Probably the limit is 24 f/3.3.


Edited by a__l, 27 January 2020 - 05:48 AM.


#36 a__l

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Posted 27 January 2020 - 05:53 AM

http://webstertelesc...c.php?f=7&t=609

 

Actually the information is from here. From the manufacturer of your telescope.



#37 Jon Isaacs

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Posted 27 January 2020 - 08:24 AM

http://webstertelesc...c.php?f=7&t=609

 

Actually the information is from here. From the manufacturer of your telescope.

 

Royal Crown bags are popular but being essentially alcohol free, the opportunity has never presented itself.

 

I use stiff baggies that are a tight fit over the Astrosystems type shell.  It's stiff enough that it projects a cylinder and the baggie doesn't contact the mirror.  I do not cover the mirror in strong winds.

 

Jon


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#38 a__l

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Posted 27 January 2020 - 07:07 PM

And when to put on a wet holder?



#39 Jon Isaacs

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Posted 27 January 2020 - 09:24 PM

And when to put on a wet holder?

 

I'm not sure what your asking?

 

I can say this, where I am located is relatively dry so humidity and condensation are not a concern using a baggie.

 

Jon



#40 a__l

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Posted 27 January 2020 - 09:38 PM

When I finish the observation, I almost always have water flowing through a telescope. As an option frost.
I was in Australia. There are similar problems. Perhaps in smaller quantities. And a hairdryer was used (heating the surface of the secondary).

Photo my 24"

Attached Thumbnails

  • 24_.jpg

Edited by a__l, 27 January 2020 - 10:19 PM.

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#41 Jon Isaacs

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Posted 27 January 2020 - 09:53 PM

When I finish the observation, I almost always have water flowing through a telescope. As an option frost.
I was in Australia. There are similar problems. Perhaps in smaller quantities. And a hairdryer was used (heating the surface of the secondary).

 

We face very different situations. My scopes rarely get wet. The mirrors rarely dew up, maybe once a year.. 

 

Jewel Valley Starsplitter JStar 1.jpg
 
Jon

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#42 Ihtegla Sar

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Posted 27 January 2020 - 11:01 PM

I'm not sure what your asking?

I can say this, where I am located is relatively dry so humidity and condensation are not a concern using a baggie.

Jon


I wonder what people who live in a humid climate should use?

#43 stubeeef

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Posted 27 January 2020 - 11:08 PM

Get ready to be blown away, also buy ibuprofen and some good scotch.

 

Congrats, you're going to love the discoveries. 



#44 Jon Isaacs

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Posted 28 January 2020 - 06:17 AM

I wonder what people who live in a humid climate should use?

I don't really know.

 

Most seem happy with the Royal Crown bag.  I saw the photo, I don't know the history of that diagonal and what else might have happened to it.  I would ask someone like Vic Menard who observes in Florida.

 

Jon



#45 jtsenghas

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Posted 28 January 2020 - 07:03 AM

I saw a clever idea for protecting a secondary on a dob of about 10" at the Cherry Springs Star Party a few years back. The homemade spider had narrow enough vanes that it extended only about an inch above the secondary.  The owner had slit a plastic peanut butter jar in four places deep enough that the jar could be placed around the secondary and the lid screwed onto it. The result was that nothing contacted the secondary and everything was practically sealed up. An elegant solution indeed,  and one that could be adapted to a variety of larger and taller plastic containers with a mouth at least as large as the minor axis of the mirror or its holder. In the mountains of Pennsylvania,  dew can be an issue on June nights. 



#46 Oberon

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Posted 29 January 2020 - 03:51 AM

Thanks,  Jon.  I need to see that photo from time to time to avoid getting overly ambitious in my builds. My 16.5" f/4.5 mirror I have squirreled away should suffice for my ultimate scope. 

 

You too need a 16” binoscope on your horizon...


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#47 George N

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Posted 30 January 2020 - 10:28 AM

…... In the mountains of Pennsylvania,  dew can be an issue on June nights. 

Dew?? Last June I stayed at Cherry Springs a few clear nights after the soggy star party -- and one night at least my Obsession 20 was covered in frost after about 2 AM. In the morning my tent was covered in a sheet of ice! Unfortunately -- the mud didn't freeze.

 

The next month I went back with my APO 'fractor for 4 nights of imaging -- and each morning I left it uncovered -- since any rain could not possibly get the scope & mount any wetter than they already were!

 

I've had my Obsession 20 dewed up *before* the sun even sets.... but I have very good dew control, and have been observing on nights at Cherry Springs where all the SCTs and most refractors have closed down -- until the fog came up - fog so thick that my red flashlight was casting a beam and I couldn't see 10 feet.


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#48 Yogurthawk

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Posted 30 January 2020 - 02:38 PM

Dew?? Last June I stayed at Cherry Springs a few clear nights after the soggy star party -- and one night at least my Obsession 20 was covered in frost after about 2 AM. In the morning my tent was covered in a sheet of ice! Unfortunately -- the mud didn't freeze.

 

The next month I went back with my APO 'fractor for 4 nights of imaging -- and each morning I left it uncovered -- since any rain could not possibly get the scope & mount any wetter than they already were!

 

I've had my Obsession 20 dewed up *before* the sun even sets.... but I have very good dew control, and have been observing on nights at Cherry Springs where all the SCTs and most refractors have closed down -- until the fog came up - fog so thick that my red flashlight was casting a beam and I couldn't see 10 feet.

Its stories like these that make me grateful to be imaging from Arizona. 

 

I only have to use a moderate dew strap for a month out of the year and that's about it. 


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#49 GeneT

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Posted 30 January 2020 - 02:59 PM

 Transportation... I'd say to seriously, very seriously consider finding a semi-permanent observing site... even if it means just rolling out of a shed. Toting the thing afield setting up / tearing down gets very old very fast. Imagery --- put it off, preferably forever. 

Enjoying the capability of biggish aperture is the goal. Anything that can defuse it becoming a chore will be to your benefit!   Tom

I agree that locating it on a permanent observing site would significantly decrease the hassle factor, and increase the pleasurable use of the telescope. 




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