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Oh Wow and Oh No!

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#1 hudder

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Posted 21 July 2005 - 07:27 AM

Hey everyone. I picked up a used C8-SGT from an Astromart seller last weekend. It's been quite the learning curve, but I've finally been able to figure out the auto alignment procedure. I guess actually knowing which stars are which by name really helps!. Anyways, after aligning the scope, I asked for M13 and it was placed within my 38mm Burgess SWA (I'm very happy with the EP BTW). Not too shabby I figured. Once I started to apply power, I was stunned!

Now, M13 did not look at all like I see in the picture. It was a fuzzy ball of barely discernable stars clumped together. As I applied power I was able to resolve some stars at the periphery of the cluster. I can see why people recommend finding a dark sky site to observe as the first thing for a newbie to do. However, I was very impressed with just being able to see it and it left me with a high degree of anticipation of what it will look like under better conditions.

I moved over to M92 and found that it was a bit brighter, but much smaller. After applying more power I really couldn't resolve any individual stars. My high power EP is an 11mm TV plossl.

Finally I slewed over to M57. This one needed my TV EP to make it big enough to really examine, but the combo of poor conditions and high power made it quite dim. Again, I'm sure a darker site would really help. Can you see colour in M57 under good conditions?

Now for some bad news and some questions. Unfortunately I made the stupid mistake of trying to put the corrector cap on in the dark. I end it up hitting the corrector plate with the edge of the plastic cap and it left (OH NO!) a few marks. From what I've read on these forums, this should not really effect the viewing through the scope (they are about 1 cm and 0.5 cm in lenght, both about 1mm in width), but they are unsightly and I know they are there. Is there any way to remove them without doing further damage? Or do I just suck it up, kick myself and live with it?

It was a great night, except for that final idiot mistake. I'm hopeing that the weather turns nice soon so I can get back out, it's going to get quite humid here. At least I can view the moon, if not for the bugs.

Mike

#2 jrcrilly

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Posted 21 July 2005 - 08:06 AM

Hey everyone. I picked up a used C8-SGT from an Astromart seller last weekend.


Hi, Mike.

That'll be a nice setup and you should get great views with it.

You have sufficient aperture to get fairly deep into the globs but it'll take dark skies and good seeing. M13 is a fairly good guide; if you look at it every night you'll see how good things are by how deep you get.

M57 takes magnification pretty well but few report seeing color in it; I know I can't even in much larger instruments.

The corrector marks aren't very important but I'm sure they are an irritation - and the longer they are left the more likely they are to become permanent. The procedure and cleaning solution described here has always worked very well for me.

#3 Tim2723

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Posted 21 July 2005 - 08:43 AM

Mike - Congrats on the new scope! You should be able to clean the marks off, but don't be aggressive! Gentle touch needed.

Hey John - After hearing people talk about this here for over two years (and probably complaining about it for over thirty!), why is it that manufacturers are still making scopes without dew shields? My Intes has one built in. It's not a very long one, but it keeps me from smacking the glass with the cover at least. Is there really so much money to be made in aftermarket dew shields?

#4 jrcrilly

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Posted 21 July 2005 - 09:01 AM

Hey John - After hearing people talk about this here for over two years (and probably complaining about it for over thirty!), why is it that manufacturers are still making scopes without dew shields? My Intes has one built in. It's not a very long one, but it keeps me from smacking the glass with the cover at least. Is there really so much money to be made in aftermarket dew shields?


Hi, Tim.

I think it's a matter of size. The C8 was created as a forkmounted scope, and the majority of SCT's are still produced in that format. With a dewshield in place, the OTA can't be parked between the forks so the package is ungainly.

#5 Olivier Biot

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Posted 21 July 2005 - 02:05 PM

Congrats with your 8" scope!

As I also own an 8" (albeit another make and brand than yours) I can tell you it's a nice instrument, and it will show you many, many objects.

Regarding color, I don't think one can observe it, as most if not all nebulae are too faint. I see nebulosity as a greenish-grayisch glow.

If you've seen M57, then try looking for M27. It is much larger and even brighter. I can even spot it with my 15x70 binoculars. Start from Sagitta, go from the tail to the head of the arrow, and then move towards the NCP about 2/3 of the length of the arrow.

As you've seen M13 and M92, try other globulars. Halfway between Albireo and the Lyre you'll find M56. It is much fainter than M13 and M92.

Another very impressive view is the Andromeda galaxy (M31) and its satellites. Unfortunately I couldn't observe them on clear skies yet, but they should be a nice summer object too.

Regarding your eyepiece set, I also own the TV 11mm Plössl for the highest magnification. It's really nice for resolving globulars! My visual back only allows 1.25" eyepieces, so I stop at a 32mm TV Plössl.

Cheers!

Olivier

#6 Joel

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Posted 21 July 2005 - 02:08 PM

Conrats on the new scope Mike! As a fellow New Englander I can tell you here lately our skies have been pretty poor with seing conditions. Summer humidity makes the seeing poor when the clouds are not around here lately. I just got a new scope and haven't had decent skies to really get good views since early July when I got it.

M13 is probably one of my favorite targets. I've seen it through a 10" Meade SNT on a good night from my yard and it looked like a pile of diamonds on a black cloth. With good seeing later in the fall when temps and humidity falls, you should be very impressed with M13 with your 8" of aperture. To me, the globular clusters, besides Saturn and Jupiter, are some of the best "neato" targets I've seen. I'm going to get started on some photography now since I got a wedge and a Meade DSI, so I'm hoping the nebulas and things like that will give me a better, if not computer aided, look at these. Clear skies!

#7 hudder

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Posted 21 July 2005 - 04:05 PM

I'm hoping that tonight will be clear for a bit so I can try my luck with some of the suggestions I've heard here on CN. I was hoping to get the scope a bit earlier in the year to get some good views of Jupiter and Saturn. Unfortunately Saturn is gone and Jupiter is always right above my neighbours roof. So the heat from the house really kills the view. I can't go much past using my 20mm EP.

One question, how can you tell whether your scope has cooled down enough? When I look at the moon and Jupiter, I see that everything is boiling. Does internal heat turbulence look any different from atmospheric turbulence? I take my tube out into the shade once the sun is behind my house and leave it until it get dark, but the views are always swimming.

I'm also looking forward to Mars getting up earlier in the night so I can take a look. Staying up till the wee hours of the morning really kill my work the next day, so I'm not a big fan of that! Looking forward to October.

Anyways, I'll leave more reports as I go along. Thanks for the advice!

Mike

#8 Olivier Biot

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Posted 21 July 2005 - 05:47 PM

It depends. On my patio where I usually observe, the roofing from the garage boxes really ruins the seeing on a sunny day. This basically means that on such a day I only have the area in the neighborhood of the zenith to observe (northern horizon totally blocked by the building I have my apartment in).

On the other hand, I guess that if you let your scope cool down the way you described, then the scope should be cool once night begins.

On this point my scope has an advantage: it doesn't have a full-aperture corrector plate (like the Schmidt lens or the Measure meniscus), but instead it uses a sub-aperture corrector lens in front of the secondary, hence leaving the OTA open! As a result, my 8" cools down very quickly, typically in 30 minutes or less. The real cool-down period depends on many parameters, like: difference in temperature outside-inside, humidity, wind speed, material of "underground" for your observing site.

Cheers!

Olivier

#9 garyc11

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Posted 21 July 2005 - 06:00 PM

a filter like the orion ultrablock will help you see nebula. some nights i cant see them without it.

#10 Burnim

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Posted 21 July 2005 - 06:07 PM

Congrats on the new scope. I passed my C8 down to my son. Great scope. You might want to collminate it though. Very important for sharpening up the clusters. I was amazed at the difference. Now I check collmination every time I view. Bob's Knobs make it quite easy.

B

#11 Olivier Biot

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Posted 21 July 2005 - 06:56 PM

a filter like the orion ultrablock will help you see nebula. some nights i cant see them without it.

Hi Gary,

Thanks for the hint! As a matter of fact, I am waiting right now for one eyepiece and 3 filters which are at the Belgian customs right now. I expect them at home in the coming week, so I can verify this :)

Cheers!

Olivier

#12 Guest_**DONOTDELETE**_*

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Posted 22 July 2005 - 01:24 AM

I'll add my congratulations on the new scope. It is definitely a fine tool. As for the marks, don't beat yourself to death about them. You might try cleaning the corrector lens to verify that the marks are indeed permanent. My guess is that even if they remain, it will be as much smaller than you currently see them.

#13 davidpitre

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Posted 23 July 2005 - 07:40 PM

Now, M13 did not look at all like I see in the picture. It was a fuzzy ball of barely discernable stars clumped together.

After applying more power I really couldn't resolve any individual stars.



I'll second the suggestion to check collimation .
If you haven't done so yet, I'll lay money it's out.
A well collimated scope is critical for decent views


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