RASA Cable Management

[tomato]

So I have followed @gorann’s lead (no pun intended) and made the power and comms cables into curves coming out of the camera, using garden wire as a former. I understand this will fix the random diffraction spikes on bright stars that you get if you leave the cables in a haphazard arrangement.

 

[gorann]

Works perfectly but I should not get all the credit. Curves do not create spikes and Vixen are selling scopes with curved spider vanes.

[ollypenrice]

21 hours ago, gorann said:

Works perfectly but I should not get all the credit. Curves do not create spikes and Vixen are selling scopes with curved spider vanes.

Curved spider vanes are common on Newts, too. Obsession use them as does David Lukehurst. They smear the diffraction artefacts around the 360 degrees so that they become scarcely visible.

Another solution for gadget lovers would be a straight cable attached to a ring which rotated slowly during the run! (Or slightly after each sub...)

😁lly

[tomato]

Something else to motorise and connect to the laptop.😊

[gorann]

2 minutes ago, ollypenrice said:

Curved spider vanes are common on Newts, too. Obsession use them as does David Lukehurst. They smear the diffraction artefacts around the 360 degrees so that they become scarcely visible.

Another solution for gadget lovers would be a straight cable attached to a ring which rotated slowly during the run! (Or slightly after each sub...)

😁lly

Interesting Olly. If I ever buy a Newton it will be one with curved vanes - why do not more offer them or maybe they can be retrofitted? I never liked star spikes (must be a Hubble fashion) and they do not make it easy to combine new and old data.

[gorann]

2 minutes ago, tomato said:

Something else to motorise and connect to the laptop.😊

Or find a way of powering the camera without cables - I think there is technology for that (have it in my electric tooth brush charger). Then it could send out the data using Wi-Fi.

[ollypenrice]

3 hours ago, gorann said:

Interesting Olly. If I ever buy a Newton it will be one with curved vanes - why do not more offer them or maybe they can be retrofitted? I never liked star spikes (must be a Hubble fashion) and they do not make it easy to combine new and old data.

They are pretty common. I have to say that I hardly ever noticed spikes, visually, in all the years that I had a 20 inch F4.1 Newt here. (That had a normal four-vaned spider.) The best Newt through which I ever observed, Ralf Ottow's legendary 12.5 inch watercooled instrument, had a normal spider and was entirely refractor-like. I didn't spend long with it, a couple of hours, but it was exquisite.

In imaging it's more of an issue. The obvious solution is to put the camera in the right place! 🤣👹🤣

Strictly joking,

Olly

[ollypenrice]

3 hours ago, tomato said:

Something else to motorise and connect to the laptop.😊

Precisely, and think of the fun you'll have on clear nights negotiating with Bill Gates!

Olly

[gorann]

2 hours ago, ollypenrice said:

Precisely, and think of the fun you'll have on clear nights negotiating with Bill Gates!

Olly

Olly, in my experience the main threat to a good imaging night are not clouds but the computers. Right now I only run one of my three obsies/rigs and it is the new RASA with one laptop only dowloading images and running PHD2. I have it in flight mode to avoid any Bill Gates interferance. However, nights are getting longer and the moon is declining so I will fire up more rigs and soon get into trouble..... Key message is stay in flight mode and no upgrades.

Edited September 8, 2020 by gorann

[tomato]

Despite adding the RASA I have managed to reduce the number of control laptops from 3 to 2. However, the laptop that has been released was running Windows 98, so updates are few and far between...😊

[wimvb]

To get rid of spikes on a Newt: put the secondary in a glass plane in front. Then to also get rid of coma, curve that glass. The camera is in the right place so as not to cause additional diffraction.

For an example of such a scope, see my signature.

[wimvb]

A high tech solution: use a drone with camera.  Rotate the hovering drone after each sub. Then you can also try guiding on that drone. I wonder if phd is up to that job?

[gorann]

4 hours ago, wimvb said:

To get rid of spikes on a Newt: put the secondary in a glass plane in front. Then to also get rid of coma, curve that glass. The camera is in the right place so as not to cause additional diffraction.

For an example of such a scope, see my signature.

Yes, the Maksutov-Newtonian telescope is a really elegant solution unless you for some reason like optic artefacts like star spikes. Still there have been rumours that SW may stop producing the MN-190, so run and buy!!!

Edited September 9, 2020 by gorann

[ollypenrice]

15 hours ago, gorann said:

Yes, the Maksutov-Newtonian telescope is a really elegant solution unless you for some reason like optic artefacts like star spikes. Still there have been rumours that SW may stop producing the MN-190, so run and buy!!!

It's a mystery to me why this design hasn't been devoloped by others, either from scratch or by using SW optics.

Olly

[tomato]

The idea is not new either, here is an OO F4 version I had in the late 1980s.

[wimvb]

On 09/09/2020 at 17:42, gorann said:

Still there have been rumours that SW may stop producing the MN-190, so run and buy!!!

If I had the funds and time for it, I would buy one and replace rhe secondary mirror with a smaller one. SW redesigned the scope at various occasions and among other things, replaced the original secondary with a larger one to cover larger sensors. But this affected contrast. A smaller mirror (combined with a small sensor) should bring this scope even closer to apo performance.

 

[wimvb]

8 hours ago, tomato said:

The idea is not new either, here is an OO F4 version I had in the late 1980s.

200 mm?

Those collimation screws could be the cause of a nervous break down. The MN190 at least has phillips screws recessed in a "well". Progress!

[tomato]

Yes, collimation was a challenge to say the least, none of the screws were spring loaded and  you could count the number of times I had  the optics reasonably aligned on the fingers of one hand. We eventually built a complete new cell for the primary mirror which helped, but it made a lasting impression on me such that my next telescope purchase after a 25 year break from the hobby,  was a refractor.