Second scope advice please

[gonzostar]

Hi

I am thinking of purchasing this refractor for AP with a DSLR. Wanting more wider field views compared to the 8"SCT

https://www.firstlightoptics.com/explore-scientific-telescopes/explore-scientific-ed-apo-102mm-f7-essential-refractor-telescope-with-hex-focus.html

I would like to know what people think of this scope. At F7 is it to slow?  I have a AVX mount to attach it to.

Or if people recommend a alternative around this price range

Cheers

Dean

[SyedT]

6 hours ago, gonzostar said:

Hi

I am thinking of purchasing this refractor for AP with a DSLR. Wanting more wider field views compared to the 8"SCT

https://www.firstlightoptics.com/explore-scientific-telescopes/explore-scientific-ed-apo-102mm-f7-essential-refractor-telescope-with-hex-focus.html

I would like to know what people think of this scope. At F7 is it to slow?  I have a AVX mount to attach it to.

Or if people recommend a alternative around this price range

Cheers

Dean

I use an ED80 with a 0.85x focal reducer which brings me down from f/7 to f/6.38 and it does the job pretty well! I don't think you would find many 4-inch triplets in this kind of price range. I had a look at the Altair Astro and Esprit triplets and they're all way above the £1,000 mark. However, purchasing the 0.7x reducer new would set you back another ~£300. Might be worth having a look on the classifieds here or on ABS? There is actually an Altair Astro 102mm f7 super ed triplet with a focal reducer included for £975 on ABS but it was put online a couple of weeks ago.

[gonzostar]

Thanks for the reply. One my concerns is the focuser. I have being told that some focusers on some refractors become a issue with a DSLR attached. Hence willing to pay for this rather then buying a more suitable focuser. Is this really a issue with skywatcher refractors? 

Would you say is there much difference between the ED80 and ED 102 apo ? 

Dean

[ronin]

The ES 102 will be a triplet the SW 80ED is a doublet, will be the main difference.

[gonzostar]

Cool. Given a choice whar  would be people prefrence for AP?

Dean

[Alien_Photons]

Dean

f7 is slow compared to f5 or f2 but this is all relative to your existing scope, mount, available time and opportunity.

I would suggest asking how much time us required to capture this object or that object at a given f stop then work back to your FOV. Decided if mosaic's are an option.

The imaging forum here on SGL or the ukastroimaging website will get you the answers you need.

[sloz1664]

Triplets reduce the blue bloat you can get with a doublet. You have no concerns with focuser worries with the Astro 102mm f7 super ed triplet.

Steve

[gonzostar]

Cheers I am looking towards triplet. But something "faster" then F7. My SCT with focal reducer if F6.3, but small FOV. Looked at the FOV calculator for astroimages with the canon. Are you happy with your 80mm triplet APO?

[sloz1664]

Yes very happy with the AA 80 ED triplet full flat field with the dedicated flattener. Nice tight round stars and no blue bloat that I had with my previous WO 71 doublet.

Steve

[Andyk93]

I had this problem a month ago, I went for the WO star71 mk2, it has 4 glass elements and doesn't need a flattener, although slightly more expensive you won't be spending money on a field flattener or the adapters to get the correct spacing. It's also f4.9 so fast enough.

[gonzostar]

Thanks for your valuable input. Also need to watch weight for avx mount. Will do more research regarding FOV etc. As for exposure times will it be similar to my 8"SCT at F6.3 at 1300mm? or would be be less day for the refractor at 700mm?

cheers

Dean