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Celestron Advanced VX 8" f/5 or f/10

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#1 will1384

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Posted 24 February 2013 - 04:51 AM

I am saving up some money for a telescope, I plan on having around $1500 to spend, it may take some time :( , but I want something that I that I can use for basic astrophotography, I have settled on two telescopes that I like, one is the

Celestron Advanced VX 8" f/5 Newtonian Reflector Telescope

and the other is

Celestron Advanced VX 8" f/10 Schmidt-Cassegrain Telescope

I feel that both would do what I want, but I think the Newtonian would be better, however my girlfriend has told me her feelings, and has made it clear she wants the Schmidt-Cassegrain telescope, she has expressed concerns about the weight, ease of use, and collimation issues with the Newtonian Telescope, and also the fact that my dad that is partially confined to a wheelchair will sometimes be using the Telescope.

I plan to store the telescope partially disassembled in a small storage shed, and the tube stored in something to keep bugs, dust, and moisture out of it, and when needed drag it out of the shed on something like the scopebuggy.

I am trying to figure out all the stuff I will need, and things to get later, and the cost associated with each telescope, here is the price list I made, to help me see the big picture, BTW I will be using a Panasonic DMC-G3 camera.

----------------------------------------------------------
Celestron Advanced VX 8" f/5 Newtonian Reflector Telescope
----------------------------------------------------------
Celestron Advanced VX 8" f/5 Telescope ----- $1,190
Beato Pro 3 Hardware Bag (UPDHB47) --------- $65
Farpoint FP403 Bahtinov Focus Mask --------- $24
Orion LaserMate Deluxe II ------------------ $70
T-Minus UltraWide Adapter for Micro 4/3 ---- $110
Knobs for Celestron Primary ---------------- $26
Knobs for Celestron Secondary -------------- $21
Celestron 18778 AC Adapter ----------------- $22
Celestron Car Battery Adapter -------------- $16
----------------------------------------------------------
-- Sub Total -- $1544
---------------Stuff we should get later------------------
Celestron Power Tank ----------------------- $55
Celestron NexImage 5 MP -------------------- $165
Coma Corrector ----------------------------- $130
---------------Stuff I want but don’t need-----------------
Celestron Accessory Kit -------------------- $125
Celestron SkySync GPS ---------------------- $167
----------------------------------------------------------
-- Total -- $2186
----------------------------------------------------------


----------------------------------------------------------
Celestron Advanced VX 8" f/10 Schmidt-Cassegrain Telescope
----------------------------------------------------------
Celestron Advanced VX 8" f/10 Telescope ---- $1600
Pelican Style Watertight Hard Case --------- $163
Farpoint FP411 Bahtinov Focus Mask --------- $25
T-Ring for Micro 4/3 ----------------------- $30
Knobs for C8 f/10 Secondary ---------------- $20
AstroZap Flexible Dew Shield AZ118 --------- $40
Celestron 18778 AC Adapter ----------------- $22
Celestron Car Battery Adapter -------------- $16
----------------------------------------------------------
-- Sub Total -- $1916
---------------Stuff we should get later------------------
Celestron Power Tank ----------------------- $55
Celestron NexImage 5 MP -------------------- $165
Universal Piggyback Mount ------------------ $32
Celestron f/6.3 Reducer Corrector ---------- $99
---------------Stuff I want but don’t need-----------------
Celestron Accessory Kit -------------------- $125
Celestron SkySync GPS ---------------------- $167
----------------------------------------------------------
-- Total -- $2559
----------------------------------------------------------

Any thing I missed, any ideas, anything else I need to buy at the same time I buy the telescope, its likely to be two to three months before I buy anything, but I want to plan ahead.

#2 rflinn68

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Posted 24 February 2013 - 08:21 AM

Hello Will. First let me welcome you to Cloudynights.

You said basic astrophotography so I am assuming you are a beginner. The SCT makes a fine scope for visual but I would not recommend it for starting out in AP. Even with a f/6.3 focal reducer the focal length is 1260mm. The VX should be a fine mount, I have took several pretty nice images on a CG5. The scope I have used and the scope I would recommend with that mount for a beginner astrophotographer is the AT65EDQ. Dont let its small size fool you. You dont need a huge scope to take nice pictures. The focal length of that scope is 420mm which is much more forgiving to tracking errors. There really are a lot of things that require this focal length to fit in the frame. I FINALLY got my C8 to work on a long exposure last night when we were out testing during a near full moon. I strongly recommend the AT65EDQ or maybe even a AT6IN but its VERY hard to beat a small refractor to start learning the ropes in AP.

I did the same thing. I bought an AT8IN and a CGEM DX and a Canon T3 camera and thought I could just go out and start making beautiful pictures. Well maybe some people can with that set up starting out but we just didnt have any luck. I wanted a more portable mount for observing with my C8 so I bought the CG5 and a little later decided I would give the little apochromatic a go with astrophotography. I wanted something with a short focal length anyway so I could frame some of the larger objects out there that just wouldnt fit with the AT8IN even though it had a relatively short focal length at 800mm. I havent looked back and IMO the CG5 (or VX) with a small apo is just perfect for starting out. You can always find a used C8 to go on your mount for observing or to try imaging the small faint fuzzies later when you get more experience under your belt.

You are also going to want an autoguider so you can get long exposure times to bring out the fainter details. Hard to beat the Orion StarShoot autoguider in either the Mini or the ST80. Anyway, thats my 2 cents on it. Good luck on your purchase, and most importantly, enjoy!

http://www.astrobin....users/rflinn68/

Rich

#3 Raginar

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Posted 24 February 2013 - 11:19 AM

rflinn68,

I agree with what you said. The SCT will make a poor choice for a first AP telescope. There are options, such as doing FASTAR (f/2), but that just adds significant cost and complexity.

And, welcome to CN, Will!

#4 Mike7Mak

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Posted 24 February 2013 - 12:07 PM

Given the OPs parameters of use I think a 65mm refractor will be a big disappointment for the other 2 people who will also be using whatever he buys. I suspect they may actually want to look through the scope.

Of the two instruments proposed the f5 newt 'might' be more conducive to 'basic AP', if it has the necessary backfocus, which I understand many newts do not.

But, for scopebuggy transport, outdoor shed storage, ease of use for observers with limited mobility, visual and AP capabilities, I think the SCT wins hands down.

Besides, that's the one his girlfriend wants. :)

#5 rflinn68

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Posted 24 February 2013 - 02:42 PM

Given the OPs parameters of use I think a 65mm refractor will be a big disappointment for the other 2 people who will also be using whatever he buys. I suspect they may actually want to look through the scope.

But, for scopebuggy transport, outdoor shed storage, ease of use for observers with limited mobility, visual and AP capabilities, I think the SCT wins hands down.

Besides, that's the one his girlfriend wants. :)


Agree the SCT will win hands down for a visual scope but he didnt mention that. He said he wanted a scope for astrophotography. A SCT is hands down the wrong scope for someone beginning astrophotography. Astrophotography and visual astronomy are two completely different things. Again, I suggest a small refractor if you want to enter into astrophotography. If you want a nice scope for observing then the SCT would be a good choice. You can buy the mount with either scope for now and buy the other OTA later and use the same mount. Or as mentioned, Fastar/HyperStar at f/2 would be excellent. That way you can use one scope for both jobs. The thing with that is the AT65EDQ is $599 and the lens for HyperStar imaging with a C8 is $799. It will be much faster at f/2 though and it will have nearly the same focal length as a much slower AT65EDQ at f/6.5 so it may be worth the extra $200 for HyperStar.

I suspect if the girlfriend wants the SCT then thats what you'll get. :grin:

Here and here is some info for Fastar and HyperStar imaging.

#6 Raginar

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Posted 24 February 2013 - 04:49 PM

It's funny, we just had this argument over in the 'mounts' forum. And, two AP guys said they'd hands down go with a AVX and an SCT (with FASTAR).

Personally, I agree with Rich. The SCT is a horrible choice to start with. But, it's the 'cool' choice for sure. But, just like all the new mounts, I imagine there will be some growing pains, and it will do as well as a $800 mount can do.

If he has 2.5-3k, I'd get a used G11 and a ED80 of some type.

Mike, I take it you know the OP? :D

#7 Mike7Mak

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Posted 24 February 2013 - 06:16 PM

Mike, I take it you know the OP? :D

I don't think so.

I was just going by what was posted with some added logical deduction, or maybe gross assumption. Attempting to answer the question asked, as it were. Not decide for him that widefield imaging is the way to go without at least asking what kind of images the OP wants to take.

The OP laid out two scopes he is considering but as per usual the boilerplate advice to buy an AT65edq comes pouring in. If the question asked was 'what's the quickest, easiest way to take widefield images' that advice would be spot on.

My opinions on this topic are obviously colored by the fact I started, and continue, imaging with a scope that wouldn't make the bottom of a long list of potential AP scopes. That and widefield imaging doesn't interest me at all. :)

#8 budman1961

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Posted 24 February 2013 - 06:24 PM

The only thing I can add it that we had a 10" Cele Newt on a CG5-GT mount, purchased that way from Celestron. I know you are looking at the 8", I feel they suffer from the same problem....wind load.

The CG5=GT is similar in capacity to the new mount, and only in the most-calm of conditions could we get anything out of the mount AP wise. We tried anti-vibration pads to help isolate it better but I hate to say, we ended up selling the OTA, and picking up an 8" Meade SCT for a song.

Are SCT's the best choice for someone new, probably not, but I would hate to see someones enthusiasm dampened with a mount that just isnt (IMHO) up the task of a larger Newt.

Andy

#9 Raginar

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Posted 24 February 2013 - 09:48 PM

Mike, totally understand :).

Andy, you're right!

#10 Footbag

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Posted 24 February 2013 - 10:26 PM

You could buy the VX and pick up a used 8" SCT and a nice used widefield refractor for about the same. I see some great deals popping up in the classifieds all the time. i love my WO66 and I saw one sell for under $250.

The widefield will be great for beginning imaging, and you'll grow into the SCT although you may outgrow the mount pretty quickl. In the meantime, you have the SCT for visual, and the widefield makes a great grab and go.

#11 will1384

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Posted 25 February 2013 - 11:23 PM

I am likely to get the Celestron Advanced VX 8" f/10 Schmidt-Cassegrain Telescope, but I also like the idea of something like the AT65EDQ, and also like the idea of autoguider, and I think I will get them both, but later, maybe next year, for the autoguider I want something a little cheaper, I was planing on getting the Celestron NexImage 5 MP, and was thinking it could also act like an autoguider when using my Panasonic G3, however I am not sure how well the Celestron NexImage 5 MP will work as an autoguider, or what extra I might need to make it work, and wonder if it may be cheaper just to get the Orion Magnificent Mini AutoGuider.

I had wanted to display the video out from the Panasonic G3, to a small LCD monitor, and use that to LCD to focus the image, but everyone kept saying there was no live video out from the Panasonic G3, but there is, sadly its only on the AV port, and looks like VHS quality video, to enable all you have to do is long press on the Q-Menu/Trash button on the camera, I wish the live video out was on the HDMI port, I was able to focus and take an image using a large TV, I will play around later and see if a small 7in LCD TV will work.

I live down a dirt road and there is a constant dusting of fine silt like dust on everything, I am getting a hard case for the tube, but what else should I do, or need to help keep the Telescope clean.

I am in the process of making a simple Barn Door tracker, two pieces of wood, a hinge, an old telescope wedge, 1rpm DC motor, 1/4-20 threaded rod, and a few custom parts that I welded, I am waiting on the motor, and clear skies, I guess that will have to hold me over until I save up enough money LOL

And thanks for the ideas.

#12 GTBaker

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Posted 26 February 2013 - 09:18 PM

Why is a SCT a bad choice for AP?

#13 Raginar

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Posted 26 February 2013 - 10:57 PM

Long focal length photography is difficult. The tolerances required are that much more difficult (guiding, image scale, etc) than at a lower focal lengths.

#14 rflinn68

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Posted 27 February 2013 - 03:44 PM

Why is a SCT a bad choice for AP?


Not so much that it is a bad choice as much as a bad choice for a beginner. Longer focal length combined with a moving mirror is not good for the beginner. Moving mirror will give you focus shift and mirror flop and can be very frustrating for a beginner in astrophotography. Its much better to start out with a camera lens or short focal length refractor. The quickest, easiest way to take widefield images is actually with a camera lens. There are several things to image though with a refractor in the 420mm focal length range that just cant be done with a scope much longer.

#15 cn register 5

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Posted 27 February 2013 - 05:53 PM

In some ways a good starting imaging/observing set up would be the 8" SCT and an 80mm ED refractor piggy backed or side by side mounted.

To start with the 80mm can be used for imaging and the SCT for guiding, then when the desire for a longer focal length come on you can image with the SCT and guide with the 80mm.

Visual work can use the SCT although some things will look better in the little scope, M44 and M45 for example.

I have, of course, spent a significant amount more of the OPs money, an ED refractor, tube rings, or SBS mount and a guide camera.

Chris

#16 Raginar

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Posted 01 March 2013 - 07:36 PM

I agree, Chris. It gives you room to grow.

#17 Craig H

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Posted 03 March 2013 - 12:47 PM

I bought basically the same package as the first option of the OP in '08, the f/5 Newt on the CG-5. I can confirm that it has enough backfocus for AP. I liked the Newt because it had enough 'oomph' for visual as well, I thought it was a pretty good compromise scope. If I had to do it all over again, I would've started with buying the mount only from Celestron and putting the A-T f/4 8" Newt on it, combination of shorter FL (800mm vs. 1000mm), shorter tube, and lighter weight (18 lbs. vs. 22 for the f/5) all would make it a better fit for the new AVX mount IMHO.

Clear skies,


Craig.

#18 Night2Fire

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Posted 03 March 2013 - 07:18 PM

Craig, That was gonna be my question to everyone. I was looking at the Celestron Advanced VX 8" f/5. I was wondering if anyone has been imaging with one would set up and say how it performs (OTA not the mount). I am looking at the F/5. How much better is the F/4 over the 5? I know if you buy the F/4 you need the CC and a laser right away, How the Comma on the F/5.

#19 Craig H

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Posted 03 March 2013 - 09:49 PM

Well, the coma is 'there' with an f/5, for some examples you can check out some shots I took with my original setup at www.flickr.com/hladys, that will give you an idea. I lived with the coma for awhile but did end up eventually buying a CC and laser.

The 8" f/4 will have worse coma, but IMHO a better scope for AP in most other respects -- baffles for extra contrast, crayford focuser, knobs for collimation... in addition to being lighter and bigger FOV than Celestron's f/5, all helpful when it comes to riding on a CG5-class mount.

Craig.

#20 FishInPercolator

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Posted 12 May 2013 - 11:29 PM

Would quality eyepieces and a paracorr2 correct any coma that exists on an f/5?

#21 gramaglia

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Posted 15 May 2013 - 05:26 PM

Regarding an SCT bad for starting AP. I sort of agree. I started with an 8' SCT wedge mounted because that's the scope I already had. I depends on the type of imager he plans on using. I started with a meade DSI II pro. The benefit of a small chip camera are the fact you can use the 3.3 focal reducer and the camera are a lot cheaper. The 3.3 focal reducer will provide decent FOV and pretty fast optics for DSOs. The larger aperture will allow for higher magnification for planets. I think it's a fair balance for a single scope that is going to be used both visually and for AP.

#22 will1384

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Posted 15 May 2013 - 10:38 PM

Regarding an SCT bad for starting AP. I sort of agree. I started with an 8' SCT wedge mounted because that's the scope I already had. I depends on the type of imager he plans on using. I started with a meade DSI II pro. The benefit of a small chip camera are the fact you can use the 3.3 focal reducer and the camera are a lot cheaper. The 3.3 focal reducer will provide decent FOV and pretty fast optics for DSOs. The larger aperture will allow for higher magnification for planets. I think it's a fair balance for a single scope that is going to be used both visually and for AP.


I ended up with a Sky-Watcher Pro 80ED refractor on a Celestron VX mount, but even with it I have trouble taking pictures, I was just able to get one good 60 second exposure yesterday, and that’s with a 50mm autoguiding setup using a cheap camera and PHD, all the rest of the images that night were bad, a big part of my problem has been that I have a very limited view of the sky, and the VX mount needs stars for alignment that sometimes I can't see, the other is that the camera I try to guide with is only sensitive enough to see brighter stars, I was recently able to get a used Orion Autoguider, I hope that it helps.

If I had it to do all over again, I would have got a real Autoguider instead of trying webcams and such, and might have gone with a better mount, I also would have saved up enough to get both the 80MM refractor for imaging and the C8 SCT for visual, to make everyone happy ;).

A few things that surprised me, and made me buy extra stuff.

I could never get good focus at night with my DSLR attached to my telescope,
until I got a Bahtinov Focus Mask.

The 50mm finder that came with the Sky-Watcher Pro 80ED was hard for me to use, so I replaced it with a telrad finder scope.

When using the proper Latitude Adjustment, pointing the tripod north, and levelling the tripod, and good GPS coordinates, I still had a lot of trouble doing the GOTO alignment, so I got a polar scope, it helped a lot.

When doing the GOTO alignment with eyepieces, I had a lot of trouble knowing what was exactly the center, so I got a 12.5mm illuminated reticle eyepiece.

I found out that my DSLR can output live video, and the SharpCap software can simulate a Reticle, so I bought a video capture device so I could use the DSLR as a Reticle.

#23 gramaglia

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Posted 15 May 2013 - 11:31 PM

If you are using PHD guiding, I suggest you also use it for polar alignment. It makes polar alignment ridiculously easy and quick to do. Let PHD do it's guiding setup routine near the meridian. Once it's guiding, tell it not to correct for DEC. Switch the graph to DX-DY. You will see the DEC line on the graph drift one side. DO a correction for east-west and start guiding again. Rinse and repeat till the DEC line is flat. Now point the telescope to either the west or the east at a low point over the horizon. Again let PHD do it's setup routine and then tell it not to correct for DEC. DO a correction for north-south and start guiding again. Rinse and repeat till the DEC line is flat. In less than 20 minutes you should have the mount perfectly polar aligned.

#24 dcbrown73

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Posted 16 May 2013 - 09:52 AM

I have an 8" SCT and an 80mm Apo. (and an AVX mount) I think it would be a big mistake to push someone to a small aperture refractor unless they absolutely were only going to use it for AP. If they have any intention on using it for visual and do not have another scope, it wouold be a HUGE mistake.

The SCT is perfectly capable of AP and even far superior to a small aperture refractor for planetary (video) AP where star drift is irrelevant. With Celestron's All-Star alignment you can easily take 60 second unguided subs with the 8" SCT with an f/6.3 focal reducer. (I do it and I'm very new at AP) Add in guiding and and you can get a lot longer exposures than that.

In my opinion, the 8" SCT on a AVX mount is easily the best solution to get the most out of your telescope purchase if it's the only telescope you will have.

Dave
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#25 will1384

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Posted 16 May 2013 - 12:37 PM

If you are using PHD guiding, I suggest you also use it for polar alignment. It makes polar alignment ridiculously easy and quick to do. Let PHD do it's guiding setup routine near the meridian. Once it's guiding, tell it not to correct for DEC. Switch the graph to DX-DY. You will see the DEC line on the graph drift one side. DO a correction for east-west and start guiding again. Rinse and repeat till the DEC line is flat. Now point the telescope to either the west or the east at a low point over the horizon. Again let PHD do it's setup routine and then tell it not to correct for DEC. DO a correction for north-south and start guiding again. Rinse and repeat till the DEC line is flat. In less than 20 minutes you should have the mount perfectly polar aligned.


That sounds a lot like what Alignmaster does, but I cant even use it, because of the limited view of the sky I have, the one spot I can see Polaris is the lowest spot of sky I can see, and its between two trees, I have no view of the horizon, and if its not almost directly overhead I cant see it.

That's one of the reasons I am having so much trouble, I am lucky to get 3 to 4 stars for alignment, and it sometime takes me 15 to 20 minutes to find then, I have to use my Android phone to help locate stars not blocked by trees.






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