Not seeing what I think I should
- Kingofthehill
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Not seeing what I think I should
As many of you know I am the owner of an Obsession 18UC. I have been able to get out a few times in the past month, which is a little more than normal for me.
There is an issue which plagues me, however: I am not seeing everything I think I should be able to see with this wonderful scope.
I believe I know the answer, but feel free to chime-in if you believe I am missing something.
First, I believe my collimation is pretty close to perfect.
Second, I use the Argo Navis, which is really good for getting darn close to an object.
Third, I am in the mountains at 5300 feet, but still in a "yellow" zone.
Last night the faintest object I could assuredly identify was a galaxy of magnitude 12.8 (I forget its number).
Surely I should be able to find things fainter than that with an 18 inch primary and very nice eyepieces.
I think what I need is darker skies.
Is there something I have overlooked? Or, should I move?
Thanks.
Main telescope used is Obsession 18UC
Cut my teeth on Orion 10" Dob
AR152 and Orion ST80 sit mostly unused
Lots of binoculars
SeeStar S50
- JayTee
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Re: Not seeing what I think I should
You live in a yellow zone. The fact that you could see a 12.8 mag Galaxy is outstanding for a yellow zone, even with an 18 inch telescope.
Please try not to judge your scope until you've had it out to at least a
Cheers,
JT
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- Kingofthehill
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Re: Not seeing what I think I should
JT,JayTee wrote: ↑Sun Aug 04, 2019 9:46 pm Hi Paul,
You live in a yellow zone. The fact that you could see a 12.8 mag Galaxy is outstanding for a yellow zone, even with an 18 inch telescope.
Please try not to judge your scope until you've had it out to at least a Bortle 2 sky, then you'll have a decent comparison from which to judge.
Cheers,
JT
Darker skies would be great. I guess I should have asked what kind of dark zones are folks in where they can catch limited magnitude objects, besides stars (13 or dimmer).
Thanks for the reply.
Main telescope used is Obsession 18UC
Cut my teeth on Orion 10" Dob
AR152 and Orion ST80 sit mostly unused
Lots of binoculars
SeeStar S50
- OzEclipse Online
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Re: Not seeing what I think I should
I have an 18"f5.6 with Galaxy optics . I observe from a site with
Zenith sky brightness information
Brightness 0.177 mcd/m2
Artif. bright. 6.18 μcd/m2
Ratio 0.0361
Elevation 689 meters
The fainter members of the Grus Quartet
NGC7590 Mv 12
NGC7599 Mv 12
are both 1'x2' in size and are both easy
If you are forgetting anything, it is that the integrated visual magnitude has to be considered in combination with the apparent diameter to give the surface brightness then that compared to the background sky brightness . Do you use a shroud? My site is so dark, I can only just see my hand in front of my face. The mirror sits in a deep rockerbox but I don't need a shroud on the trusses.
Previous owner of the scope told me he just detected Polarissima Australis NGC2573 Mv 14.55 (30"x60") from dark skies. I prefer to use the larger
Hope this helps
Joe
Amateur astronomer since 1978...................Web site : http://joe-cali.com/
Scopes: ATM 18" Dob, Vixen VC200L, ATM 6"f7, Stellarvue 102ED, Saxon ED80, WO M70 ED, Orion 102 Maksutov, ST80.
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Re: Not seeing what I think I should
Refractors: ES AR152 f/6.5 Achromat on Twilight II, Celestron 102mm XLT f/9.8 on Celestron Heavy Duty Alt Az mount, KOWA 90mm spotting scope
Binoculars: Celestron SkyMaster 15x70, Bushnell 10x50
Eyepieces: Various, GSO Superview, 9mm Plossl, Celestron 25mm Plossl
Camera: ZWO ASI 120
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- Bigzmey
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Re: Not seeing what I think I should
My home is in yellow-orange zone. Even the brighter galaxies are reduced just to their cores. Two hour drive east takes me to the green-blue zone. The galaxies come alive. Even in 4" scope I see details in the disks, which are not visible in 8" from home.
Mounts: SW: SkyTee2, AzGTi; iOptron: AZMP; ES: Twilight I; Bresser: EXOS2; UA: MicroStar.
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- Kingofthehill
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Re: Not seeing what I think I should
I'm trying to organize, in my head, a fall trip to Death Valley with mountain camping.
Main telescope used is Obsession 18UC
Cut my teeth on Orion 10" Dob
AR152 and Orion ST80 sit mostly unused
Lots of binoculars
SeeStar S50
- SkyHiker
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Re: Not seeing what I think I should
Death Valley can be good but is not the greatest IMHO. There can be dust in the air and the light dome of Vegas is a problem. Try the mountains West of 395 for instance the Horseshoe Meadows campground at 10000 feet. The Alabama Hills are also quite good. Avoid forest fires, there can be several several going on. Many astronomers from LA go to the Mount Pinos parking lot at New Moon. The Big Bear Lake area is also good. The RTMC is happening there in September at 7000 feet, you can camp there and have a super astro conference time though the Moon is not in an ideal position.Kingofthehill wrote: ↑Tue Aug 06, 2019 4:12 am Suspicions confirmed, I need to find darker skies. I have been considering overall size of object when considering magnitude, knowing that as size increases and magnitude stays constant, relative visible brightness decreases.
I'm trying to organize, in my head, a fall trip to Death Valley with mountain camping.
- helicon Online
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Re: Not seeing what I think I should
I also like the White Mtns straddling the Nevada - California border. About as dark as you can get. In the daytime you can see the ancient Bristlecone pines.
Refractors: ES AR152 f/6.5 Achromat on Twilight II, Celestron 102mm XLT f/9.8 on Celestron Heavy Duty Alt Az mount, KOWA 90mm spotting scope
Binoculars: Celestron SkyMaster 15x70, Bushnell 10x50
Eyepieces: Various, GSO Superview, 9mm Plossl, Celestron 25mm Plossl
Camera: ZWO ASI 120
Naked Eye: Two Eyeballs
Latitude: 48.7229° N
- Kingofthehill
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Re: Not seeing what I think I should
Bristlecones are awesome trees. Thanks.
Main telescope used is Obsession 18UC
Cut my teeth on Orion 10" Dob
AR152 and Orion ST80 sit mostly unused
Lots of binoculars
SeeStar S50
- Kingofthehill
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Re: Not seeing what I think I should
Thanks for the suggestions, I'll take a look at logistics.SkyHiker wrote: ↑Tue Aug 06, 2019 6:44 amDeath Valley can be good but is not the greatest IMHO. There can be dust in the air and the light dome of Vegas is a problem. Try the mountains West of 395 for instance the Horseshoe Meadows campground at 10000 feet. The Alabama Hills are also quite good. Avoid forest fires, there can be several several going on. Many astronomers from LA go to the Mount Pinos parking lot at New Moon. The Big Bear Lake area is also good. The RTMC is happening there in September at 7000 feet, you can camp there and have a super astro conference time though the Moon is not in an ideal position.Kingofthehill wrote: ↑Tue Aug 06, 2019 4:12 am Suspicions confirmed, I need to find darker skies. I have been considering overall size of object when considering magnitude, knowing that as size increases and magnitude stays constant, relative visible brightness decreases.
I'm trying to organize, in my head, a fall trip to Death Valley with mountain camping.
Main telescope used is Obsession 18UC
Cut my teeth on Orion 10" Dob
AR152 and Orion ST80 sit mostly unused
Lots of binoculars
SeeStar S50
- helicon Online
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Re: Not seeing what I think I should
Refractors: ES AR152 f/6.5 Achromat on Twilight II, Celestron 102mm XLT f/9.8 on Celestron Heavy Duty Alt Az mount, KOWA 90mm spotting scope
Binoculars: Celestron SkyMaster 15x70, Bushnell 10x50
Eyepieces: Various, GSO Superview, 9mm Plossl, Celestron 25mm Plossl
Camera: ZWO ASI 120
Naked Eye: Two Eyeballs
Latitude: 48.7229° N
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