TheSkySearchers

Posted: **Tue Oct 29, 2019 8:17 pm**

Kos wrote: ↑Tue Oct 29, 2019 2:22 pm Bigzmey, добрый день!

Скажите пожалуйста, вот вы в своей статье рекомендуете читателям применить катадиоптрический телескоп, диаметром 5-11 дюймов. Мне вот интересно, а почему вы не порекомендовали телескоп Ньютона? У него ведь ниже % центрального экранирования, нежели у Шмидт-Кассегрена или Максутова-Кассегрена. Ведь по законам оптики выходит, что Ньютон должен быть "резче" в связи с малым центральным экранированием. Термостабилизация опять же у Ньютона лучше.

Спасибо за комментарий к моему вопросу!
Чистого неба!

Thanks for the comments Kos! I agree, good quality (preferably slower) Newts or DOBs could be fine planetary instruments. I saw stunning images of Jupiter coming out of well made larger DOBs. However, if you take a mass produced telescope, on average you would get better planetary views with CATs over Newts/DOBs.

Typically, slower scopes provide steadier views of planets, they have less optical aberrations and do not require well corrected (and expensive) EPs to get good views. From this point of view CATs have clear advantage over fast Newts and DOBs.

Another, consideration is that entry level Newts are in a different price category than CATs and as a result made with larger tolerances and cheaper components. Combined with fast optics the image tends to degrade faster at higher magnification than in CATs. More often than not I see users stopping down Newts and DOBs to achieve acceptable views of planets, which in turn decreases resolution.

BTW, it is not just fast Newts. From my experience fast achro refractors (even though they don't have a central obstruction) are not as good on planets as small MAKs and SCTs. I love my 6" achro refractor. It is a superb DSO machine. But my 5" Mak (with about half of light gathering power) delivers much better planetary views at less than half price.

Posted: **Wed Oct 30, 2019 7:00 pm**

Thefatkitty wrote: ↑Fri Oct 25, 2019 2:03 am Hi Andrey,

Thanks again for another informative article! I learned a few things, most notably about observing planets. I thought I was missing a lot, as the Moon, planets, and brighter DSO's I see from home, but at a dark site, I mostly go after DSO's. I took a look at Jupiter a few times at said site, and was underwhelmed to say the least. I remember thinking it seemed better from home, but that can't be right....
Well, I guess it is, thanks for that! Now I know I'm not losing my mind/sight, yet

Interesting as well about the diagonals. I have a total of two I use; an iOptron dielectric I bought as an open box special for $80 CDN, and the diagonal that came with my orange circle-V Celestron 80mm. That one uses a prism, which I cleaned as I would a scope mirror. Here's a pic of the two:

diag.jpg

Simply put, I think the Celestron prism diagonal is the better of the two. A slightly wider FOV; more noticeable in my long f/l fracs, and better overall detail on planets. As well, double stars are just that much easier to resolve. Background darkness is really the same in both.
A good example would be the Trapezium in Orion. Using my 80mm f/15 and the prism diagonal and a KK ortho 12.5mm, I can easily pick out the four main stars on a good night. Switch the diagonal with the dielectric, and yeah, they're there, just not as easy to see and defined to look at. Not sure how else to put that, but there it is...

I'm sure my lowly prism is no match for a Baader, but again, I couldn't figure how it beat out a low-mid range dielectric, what with it being 99% reflective and all. Now I know!

Again, thanks for all that Andrey. I hope you have a few more articles to come, I'll enjoy the read I'm sure!

All the best,

I missed your posting before Mark, these older Celestron made by Vixen prisms were of quite good visual quality and I would recomend them if coming across one for a good price used.
I only replaced mine when I purchased my Zeiss/ Baader 2" prism which is one of my most used diagonals.

Posted: **Mon Jan 27, 2020 7:04 pm**

Thanks for your excellent article. Glad that highend diagonals and Ortho's are made part of the knowledge about planetary observing again. I have never felt the need for colorfilters, tried them, maybe I am a purist or just a stubborn old observer. I embraced the Atmospheric Disperion Corrector though ( special in this decade, with the big ones low on my horizon).

Posted: **Mon Jan 27, 2020 7:42 pm**

John Baars wrote: ↑Mon Jan 27, 2020 7:04 pm Thanks for your excellent article. Glad that highend diagonals and Ortho's are made part of the knowledge about planetary observing again. I have never felt the need for colorfilters, tried them, maybe I am a purist or just a stubborn old observer. I embraced the Atmospheric Disperion Corrector though ( special in this decade, with the big ones low on my horizon).

Thanks John! The color filters from cheap planetary sets are worthless, but good quality color filters do help to resolve low contrast features like Saturn banding or Mars mares. Even with Moon I prefer now orange filter for crescent and green for near full phase over neutral.

Atmospheric Dispersion Corrector sounds interesting, it looks like it adds quite a bit of focuser travel. Do you skip diagonal when use it?

Posted: **Sun Sep 27, 2020 12:32 pm**

Leaving porch light on while observing Moon and bright Planets was my best takeaway from your article. Thanks.

Posted: **Mon Sep 28, 2020 3:37 am**

deg13122 wrote: ↑Sun Sep 27, 2020 12:32 pm Leaving porch light on while observing Moon and bright Planets was my best takeaway from your article. Thanks.

Sure thing!

Posted: **Sat Oct 10, 2020 3:05 pm**

I've had to deal with increasing LP including local lights which are hard to screen out. Good suggestion!

Posted: **Sat Oct 17, 2020 2:25 am**

This is a wonderful article, Bigzmey !
Very well done.

Posted: **Mon Oct 19, 2020 3:55 pm**

John Donne wrote: ↑Sat Oct 17, 2020 2:25 am This is a wonderful article, Bigzmey !
Very well done.

Thanks John!

Posted: **Tue Dec 01, 2020 3:28 pm**

well done , thx .

Posted: **Tue Dec 01, 2020 7:41 pm**

messier 111 wrote: ↑Tue Dec 01, 2020 3:28 pm well done , thx .

Thanks Jean-Yves!

TheSkySearchers

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Re: How to observe the Moon and planets

Re: How to observe the Moon and planets

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Re: How to observe the Moon and planets

Re: How to observe the Moon and planets

Re: How to observe the Moon and planets