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Flattener Only For William Optics GT81
Posted: Wed Sep 01, 2021 4:35 am
by astrographymc
Are there any "only flattener (not reducer)" that can be used with WO GT81? I want to use the focal length 478mm for the scope , not the reduced 382mm with their dedicated reducer flattener Flat 6AIII. I have come across these two followings. Can those be used with the scope?
1. Ho Tech SCA Field Flattener 2"
2. TSFLAT 2 Universal flattener
If those can be used, how about the backfocus? Will I need any extension ring? Have anyone used this ?
Please help.
Re: Flattener Only For William Optics GT81
Posted: Wed Sep 01, 2021 2:59 pm
by chris_g
astrographymc wrote: ↑Wed Sep 01, 2021 4:35 am
Are there any "only flattener (not reducer)" that can be used with WO GT81? I want to use the focal length 478mm for the scope , not the reduced 382mm with their dedicated reducer flattener Flat 6AIII. I have come across these two followings. Can those be used with the scope?
1. Ho Tech SCA Field Flattener 2"
2. TSFLAT 2 Universal flattener
If those can be used, how about the backfocus? Will I need any extension ring? Have anyone used this ?
Please help.
What little I know about the physics of the lenses, I don't see why they would not work, I'm sure someone will correct me if I am wrong. If I were to choose between the two, I would go with the TSFLAT2, the back focus requirements is 109mm with exceptions, so If you're using a
DSLR, you'll need 54mm additional. It's 2" on both sides and it lets in more light. It also can be used for visual if that is your fancy.
https://www.astroshop.eu/flatteners-cor ... r_1_select