Draco dwarf easier with a 6"?

[Ivan Maly]

Oh, you have exposed aluminum there... Yes, that I would paint over at leisure. The negative results of your experimental approach with the shield are interesting. That said, a length that is equal to the diameter is the absolute minimum to expect any effect theoretically. That's against stray light from the sky; I assume the shield was built originally to be used against local light sources in a backyard situation.

[akarsh]

Oh, you have exposed aluminum there... Yes, that I would paint over at leisure. The negative results of your experimental approach with the shield are interesting. That said, a length that is equal to the diameter is the absolute minimum to expect any effect theoretically. That's against stray light from the sky; I assume the shield was built originally to be used against local light sources in a backyard situation.

Hi Ivan

The light shield was made to avoid star light from the sky -- not local light sources. John Tatarchuk, the previous owner of the scope, almost exclusively observed from Bortle 2 or better skies. It does seem to be at least 18" long, which makes sense.

I wouldn't read too much into the experiment of "blinking" the shield, because I was not doing it in a very controlled manner.

Yes, I should paint that exposed aluminum. Thanks for your pointers!

Regards
Akarsh

[akarsh]

Interestingly, I observed Palomar 15 a few hours ago, and the 18" clearly won over the other smaller scopes. The object was detected in the 18" as a slight increase in background brightness, and the exact location was confirmed using a POSS2 image. The observation could be reproduced repeatedly quite easily, by tapping the telescope a bit. In a 12" Hardin Optical dob, the object was hardly visible, and if at all, was felt on few occasions. In the 6" SkyQuest, even the reference stars were very faint.

Since this too, is a contrast-limited observation, I expected the 12" to yield. The 12" is cerainly not baffled well, but yet, this seems to indicate that there is value in larger aperture even for such low-contrast objects (as is to be expected).

Clear Skies
Regards
Akarsh