Dedicated planetary telescopes

[Stefan Buda]

Originally Posted by Wilso

Corrector plate vs spider veins?

That is a bit complicated as it is like like comparing apples and oranges.

Have to compare transmissivity with obscuration and scatter with diffraction.

I don't know the exact numbers for the corrector plate, but the light loss due to spider vane obscuration will be 1.6% of the clear aperture, on top of the 7.4% caused by the central obscuration.
Light scatter by the two air/glass surfaces of the corrector plate is probably more detrimental than the diffraction effect of the spider vanes, considering how difficult it is to maintain the corrector in a pristine state free of any condensates.
Also most of the energy diffracted by the spider vanes falls outside of the planets image, thus not degrading the contrast on the planet.

[Tulloch (Andrew)]

To control dew on my C9.25" SCT I use a portable fan heater, others use a hairdryer. Just blow warm air onto the corrector plate and once the dew is gone, wait for about a minute for the corrector to get back to ambient temperature and start imaging.

This FAQ might help you in your Planetary AP journey.

https://www.cloudynights.com/topic/8...eptember-2024/

[Stefan Buda]

Originally Posted by Tulloch

To control dew on my C9.25" SCT I use a portable fan heater, others use a hairdryer. Just blow warm air onto the corrector plate and once the dew is gone, wait for about a minute for the corrector to get back to ambient temperature and start imaging.

This FAQ might help you in your Planetary AP journey.

https://www.cloudynights.com/topic/8...eptember-2024/

I used a hairdryer too, a long long time ago when I started planetary imaging with a 180 Maksutov. Not a good idea to heat your optics when you try to image at the theoretical limit of your scope, but if you get dewed up there is no other option.

Your link is a good place to start for beginners, however, I would not recommend planetary imaging with scopes below 250mm aperture.

[Leo.G (Leo)]

I have a couple of hair dryers which I never use for my hair (my son and I both have long hair to our waists (lower but I don't want another infraction even if I ### out a word) and long beards), I do however use them on telescopes, mainly only on cool but if I need the heat I run low heat, low speed air for a minimal time period. They have been my saviour for many years with astronomy through winter in Lithgow where minus 12 is common through our winter nights. Though we've just had our first winter I've not taken a telescope or camera out once, first time in over 30 years (personal problems and mind set). I'm a little annoyed with myself though, I'm sure I've missed so many beautiful image opportunities.......

[Stefan Buda]

I achieved some progress with my DK250 project and I will start a dedicated thread to document it in the ATM section.

[Stefan Buda]

New thread started: https://www.iceinspace.com.au/forum/...d.php?t=211657

[Tulloch (Andrew)]

Originally Posted by Stefan Buda

I used a hairdryer too, a long long time ago when I started planetary imaging with a 180 Maksutov. Not a good idea to heat your optics when you try to image at the theoretical limit of your scope, but if you get dewed up there is no other option.

Your link is a good place to start for beginners, however, I would not recommend planetary imaging with scopes below 250mm aperture.

Larger scopes are certainly better, but it's definitely possible to get nice images of the planets with smaller scopes. Here are some images I've taken with my 6" SCT.

My C9.25" (with "only" 235mm aperture) is certainly capable of taking great images of the planets (they are the ones in the FAQ) in good seeing.

[Stefan Buda]

Originally Posted by Tulloch

Larger scopes are certainly better, but it's definitely possible to get nice images of the planets with smaller scopes. Here are some images I've taken with my 6" SCT.

My C9.25" (with "only" 235mm aperture) is certainly capable of taking great images of the planets (they are the ones in the FAQ) in good seeing.

For nice images aperture doesn't matter. Your small bore images are good and they show how far you can get with a 6" aperture. But that is the end of the road for that aperture and if you are happy to stop there then no problem.
When I say 250 as a minimum, I mean something bigger than the next standard size down, which is 8". The C9.25 is a weird size but it fits my criteria as it is closer to a 10" than to an 8".