Lightweight Visual Back for a 180 Mak with Micro-Focusing

[alex_stars]

Dear Stargazers,

I have been searching for a new visual back for my 180 SkyMax Mak-Cass, especially with micro-focusing ability. My 180 Mak has a standard 2" SC thread on the back so the obvious choice would be a Crayford style aftermarket focuser with 1:10 micro-focusing. However I did not like the idea to add about 750 g of focusing equipment to my telescope when my heaviest "payload" is 522g, thats visual with a 1.25" diagonal, an ADC and the Hyerflex zoom EP.

So I was thinking a bit and came up with the following setup, both for visual as well as planetary photography. Here is the shopping list:

• 2" SC to T2 rotatable adapter (there is a Baader one, I went for the TS TSSC-T2S adapter)
• 2x T2 - Baader 1.25" focusing EP holder (T-2 part #08A or #2458125)
• a 40 mm T2 extension or an ADC with T2 treads (I have both)
• a micro-focusing diagonal (I converted my TS 1.25" diagonal with one of the two Baader #08A EP holders and this TS ZS1D-T2 adapter)

Now first some images of the 1.25" diagonal conversion:

off goes the standard EP holder and mount the T2 adapter:

and on goes the Baader #08A EP focusing holders

well that was straightforward, but it's nice to focus the EP directly on the diagonal.

Onward with the new configuration. I removed the standard visual back and the 2" to 1.25" adapter I used to use:

and mounted the SC to T2, the 40mm T2 extension and the Baader #08A EP holder. This setup is about 100g lighter than the original VB. It places a camera at FL = 2477 mm and one can directly micro-focus the camera.

Another setup is with an ADC:

where this setup is about 70g lighter than the original VB and places the camera at FL = 2400 mm. Again micro-focusing is achieved with the Baader #08A EP holder.

Now when it comes to observing planets, an ADC is quite crucial in the next few years to come so I mounted it as seen above. You can level the ADC with the SC to T2 adapter, which is rotatable, but you can also easily lock it in place by tightening the outer ring with the grooves. Add the now focusing diagonal and your favourite EP and:

You are ready to observe at an FL = 2730 mm (almost stock FL). The advantage is that you can easily rotate the diagonal with the first Baader #08A EP holder (before the diagonal in the light path) and then focus your EP with the second Baader #08A at the diagonal. 😀

I like this setup, both because it is very lightweight and also versatile. Downside is that you can not add a motor focuser, which I don't mind. I will test this setup extensively now during October (Mars!!) and report back on how it performs when using it out at night.

Let me know what you think about the setup. Hope its useful to anyone.

Clear Skies,
Alex

Edited September 29, 2020 by alex_stars

[alex_stars]

After last nights (30.09.2020) imaging session, where I also tested my visual setup, I am very happy to report that the above setup works very well. Micro-focusing is no issue and the Baader #08A offers plenty of focusing option in combination with the Skymax 180.

Here a link to some images I just posted on SGL. Never got the focus so far that sharp on my Mak. 😀

https://stargazerslounge.com/topic/363617-sept-30th-jupiter-saturn-moon-and-mars/

Clear Skies,

Alex