Advice on Refractor or Reflex lens for use on Skywatcher Star Adventurer Mount

[spaceslug]

I may be in the market for a small refractor to add to the Skywatcher Star Adventurer mount, for casual observational and astro-imaging use. I have a 300mm prime lens for my DLSR and this works well but I need to get in a bit closer. On a budget so nothing too fancy but I do want reasonable quality. I note the ED80s from Orion and Skywatcher seem to come highly recommended. Anyone using these on a Star Adventurer, or any other suggestions/recommendations please/

One cheap alternative I've been pondering is to get a 500mm reflex lens for the Nikon. I used to have a Tamron years ago for use at airshows, but being manual and f8 it didn't really suit aircraft although given the right conditions it was pin sharp. Anyone used anything like this at all? 

TIA.

Mike

[Davey-T]

Guess you'll need something with a bit of focal length which will make it long and heavy, neither of which are a good thing for the SA or transporting, maybe a shorter focal length plus a barlow would work ? or a small Mak.

Dave

[Fozzie]

How about a Nikon Teleconverter to quote the product blurb..

"A teleconverter allows you to increase the apparent focal length of a lens, giving you a greater telephoto effect than a lens alone. A teleconverter is basically a magnifying lens that is placed between the camera body and lens. Teleconverters are favorite accessories of nature and wildlife photographers, because they allow them to extend the photographic reach beyond what might be safe when on safari or in an unfamiliar location. In general, wide-angle prime and zoom lenses are not compatible with teleconverters; which makes sense, since you’re using a teleconverter to increase your reach—and you’d likely start out with a longer focal length lens to begin with. Using a teleconverter is an affordable option when you want to increase your photographic reach without having to purchase new super-telephoto lenses.  Nikon currently offers teleconverters in 1.4x, 1.7x and 2x magnifications. "

http://www.nikonusa.com/en/learn-and-explore/article/h7ruielh/using-teleconverters.html

I've not used one and to clarify, I've had a DSLR for about 2 weeks, so REALLLY don't know anything about DSLR lenses etc..  but came across these on line..

Price wise they look to be in the region of a ED80 and I bet you can probably pick them up second hand.. 

Don't know if that is a viable suggestion, certainly lighter than an ED80, which would help with the SA mounting.

Ta

Fozzie

[billyharris72]

I thought about getting a mirror lens myself, but overall the reviews I've read for these are very mixed and ended up putting me off. I think the Tamron lens is regarded as about the best there is within a sensible price range (there is also a Zeiss one, supposed to be better, but even second hand it'll set you back considerably more than a new ED80).

Optically, no doubt the ED80 would be a better bet, but you may struggle with the longer tube and being right on the limit of the mount (once camera etc is added).  A decent reflex lens - if you can find one - basically is a small, fast (though still slow for astro) Mak. Better still might be a 1.4x teleextender with a 30mm prime telephoto. Would get you a bit closer, with better optical quality and very little gain in weight.

Billly.