Grab N' Go Alt-Az Adventures: Orion 8” f/4.9 ...
Posted 08 May 2014 - 04:58 AM
Posted 08 May 2014 - 05:30 AM
Here is my current Grab and Go manifestation.
Posted 08 May 2014 - 08:46 AM
I've been trying to figure out what to put on my Unistar Deluxe other than my little SVR-70, and that 8" f/4.9 sounds perfect. I should probably upgrade my tripod to something heavier than the 'light' UA tripod, however.
Posted 08 May 2014 - 03:15 PM
Posted 08 May 2014 - 07:59 PM
The 8" f/4.9 works fine on this mount. I can imagine a 6" f/5 Newt on the Unistar would be rock steady.
One of the reasons I wrote this article was that I did not feel the alt-az tripod-mounted Newt has been given its due.
Posted 09 May 2014 - 04:18 AM
Posted 09 May 2014 - 07:59 AM
Posted 09 May 2014 - 01:50 PM
Thanks for your effort.
Posted 09 May 2014 - 07:58 PM
Nice review, Phil! I was looking forward to it, and was not disappointed. Looks like a good match. Funny, I was just speaking with a friend and fellow CN'er last night about a mount for his C102 refractor. The Unistar may be a good way for him to go, as well. As you note, telescope weight is only one aspect of mount selection. Moment arm is a much bigger factor than many consider.
Thanks for the kind words on the review.
Yeah, the moment arm makes a lot of the weight ratings a bit inflated. Even though a C11 OTA weighs about 28 lbs., it's only 24"-long, and I'd be willing to bet it's close to the vibrations seen with the 38"-long, 17-lb. 8" f/4.9 OTA--not instantaneous dampening, but not bad.
I wanted the 8" f/4.9 on there to get a combination of portability, aperture, and field of view. If settling for the first two criteria at the expense of the third, a C11 seems like an attractive option on this kind of mount and tripod.
The nice thing about the 8" f/4.9 is that the OTA goes for about $200 on the used market--almost dirt cheap for the aperture. Actually, I know of someone who *literally* got one dirt cheap! Columbus amateur Chulk Gulker was bicycling around Dublin, OH, and saw one on the curb on trash day. He went back, cleaned it up, and it turned out the mirror was okay. As they say, "one man's trash is another man's treasure."
Posted 10 May 2014 - 12:38 PM
Great article! I've been playing with an 8" f/5 myself for probably the exact same reasons...want a good size aperture, but also a portable package, and in a design not as picky as a closed tube like and SCT can be. On a small alt-az I had the same impression as you...it really is a joy to use and resparks your interest. It is just plain fun!! In the end, I think it is an overlooked setup. In many ways I find it an optimum portable 8" telescope for visual (and imaging if you like GEMs). Also the entire setup can be very light. I think if you put a good dual speed focuser on it you will begin to think that it is much more than just a generalist, but really an unheralded master of fun do everything scope that provides a masterful view when equipped with a good mirror, secondary, and focuser. An 8" f/5 Newt IMO is quite a masterful instrument that when properly appointed takes a second seat to almost none of the same aperture class.
Posted 10 May 2014 - 03:11 PM
In a set of circumstances that can only be explained by Rod Serling...I now have TWO Orion 8" f/4.9 OTA's as of a few hours ago.
I bought a second one off of that other site. Why, pray tell do this, when I've got one with a Lockwood mirror? Because the OTA I bought is (a) flocked, like mine is, ( has a cooling fan attached, and, oh yeah--© it has a dual-rate Moonlite focuser installed. And it priced in a way I couldn't resist.
Provided the secondary mirror has no issues, I can simply swap the mirrors between the new tube and my current one. The resulting hybrid will be an 8" f/4.9 with (a) flocking, (b ) cooling fan attached, © a buttery-smooth Moonlite dual-rate focuser, (d) an 8" Mike Lockwood optic in the engine room, and (e) a GLP to hone in quickly on DSO's.
The previous owner's mirror? Pop it in my current OTA with the stock focuser, and probably sell it at some point to defray the costs of getting the Moonlite. I don't know anything about the prior owner's mirror figure, but it's probably better than the stock mirror I started with.
No, I'm not thinking binoscope at this point. I've got some decisions to make regarding the "new guy". If I ever wanted to do imaging, an 8" f/4.9 makes for a nice platform.
But for sure, the Moonlite and the Lockwood are going to be on the same scope.
Posted 11 May 2014 - 07:18 PM
Keep up the good work.
Posted 13 May 2014 - 12:37 AM
Posted 13 May 2014 - 07:52 AM
I had my first (very) limited observations with the hybrid scope on Saturday night. My Unistar mount is bolted directly onto the 235mm rings that hold the scope, so I simply swapped tubes. I then removed both mirror cells and swapped mirrors before putting both cells back in their respective tubes.
This was a bit more involved than simply swapping the mirror cells, but it was done for two reasons. First, by keeping the cells in the same tubes, I didn't have to worry about alignment hole variation between each tube. Second, the seller's mirror cell had the cooling fan installed, thus making it easy to remember the alignment of the cell in respect to the optical tube.
The Moonlite focuser is just buttery smooth. The stock focuser on the Skyview Pro 8 is fine, but this is in another league. Combining a Moonlite with a Lockwood Mirror and tube flocking truly makes this feel like I bought a high-end 8" apo with mere mortal finances. The guy who had this scope used it for imaging, so he used a focuser with no spacers and an extension tube for visual work. Since I was doing visual, I left the extension tube in, and I can use my eyepieces just fine with this set-up, BUT...
...there's a small gap between where the focal plane of the base focuser will extend out to, and where the focal plane could be racked into with the extension tube. And guess what falls into that gap, boys and girls? Why, the sweet spot for the Paracorr, of course! I didn't have the in-focus with the extension tube, but I had to really dangle that thing out w/o the extension tube in order to focus. (Aaargh!).
So I'm not done yet; I'll take some exact measurements and order a spacer from Moonlite. Not an expensive fix, but an unanticipated, last-minute temporary spike in the PITA Factor.
Posted 17 May 2014 - 09:24 AM
Posted 17 June 2014 - 05:51 PM