Spec me a frac

[Shelster1973]

Having now packe away all my kit for my house move, have decided that even though I have customised my 8”newt to what I want, I think it may not get resurrected and am wanting to move down the frac route.

Just want to get a few opinions on way to go.

Have ideally £1750 to spend, but can go up to £2000 if worth it.

Will be mounted on an EQ6-R Pro and data collection will be either a D7100 or my SXVR-H694 mono CCD with associated Badger RGBL and Ha filters.

As I will be imaging, field flattened will be a given in the cost.

Have ben contemplating the SkyWatcher 150 ED that came out a few months back, but have not seen any reviews on its imaging capability yet and there have been a few comments about the quality on receipt.

So then....over to the great people of SGL....help me spend my money

[vlaiv]

18 minutes ago, Shelster1973 said:

So then....over to the great people of SGL....help me spend my money

Ah, that is mighty nice of you! I bet everyone here likes spending other people's money

So here we go, if I were into large 'frac imaging with that kind of budget, this would be my choice:

https://www.teleskop-express.de/shop/product_info.php/language/en/info/p6679_TS-Optics-PHOTOLINE-130-mm-f-7-Triplet-APO---FPL53---2-5-inch-RPA-focuser.html

With "suitable" reducer / flattener:

https://www.teleskop-express.de/shop/product_info.php/info/p5120_Riccardi-Reducer-and-Flattener---42mm-field---0-75x-for-Refractors-and-RC.html

 

 

[Shelster1973]

Cheers for that.

Having a look see, am thinking of upping my budget as this will be a long term scope, so happy to invest a bit more.  Now contemplating getting one of these.  Am liking the look and going down the carbon fibre route will reduce load on mount and hopefully give a more stable platform.  Plus, anything in carbon fibre is cool ?

Just need to find a flattened (if its needed) and all will be good.

 

[ollypenrice]

28 minutes ago, Shelster1973 said:

 Plus, anything in carbon fibre is cool ?

 

 

In fact anything carbon fibre is actually rather warm.  In open tube designs this doesn't much matter but with a closed tube I suspect that a less insulating material is to be preferred. If carbon were the right material it would be used by the best refractor manufacturers but it isn't. (Astro Physics, TEC, Takahashi.) 

First I'd think about focal length. So many of the nebulae are remarkably large, so needing a short FL.

If you'd like to image smaller targets you need to work out your pixel scale. I find that about 0.9"PP is often, but certainly not always, sustainable in my skies and when it isn't I can shoot colour and leave luminance to another night. Using OSC you'd need to bear in mind that you won't be able to do this so a very fine pixel scale in a longer FL would, on nights of dodgy seeing, crop your field of view but deliver no new detail. I can also rely on our Mesus to deliver a tracking accuracy of about a third of an arcsecond. I don't know what your values are for your EQ6 but the RMS in arcseconds needs to be about half your pixel scale for it to support that resolution.

I do like doing high res imaging in a larger refractor but it comes with the caveats above.

Olly

[Shelster1973]

Well

after much deliberation I now think I will get myself an Altair Wave Series 102mm F7 Super ED Triplet Apo with a field flattener too.

The FoV calculator looks OK for that one and will be within my price range.