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First light with 1278 #15 Part 1

Started by tomhole, 11/20/2003 08:58PM
Posted 11/20/2003 08:58PM Opening Post
Hello,

1278 #15 arrived safely today via FedEx. After the obligatory "whadidya buy now?" from my better half, I quickly opened the package. Bill did a superb job packing the scope to insure its safety. He added two pieces of PVC pipe to keep the box from getting crushed length wise. No damage anywhere that I could spot. First hurdle overcome.

Before I move on, I think a little background on my GEM and refractor experience is in order. I have none. I do have an ST80 on my XT10 as a finder, but it only sees a 32mm plossl. No purple haze at 13x. Nice 4 deg TFOV, though. My only telescopes up till now has been an XT4.5 dob, and my trusty XT10, 10", f/4.7 dob. So, you get to here what a newbie thinks of GEMs and refractors.

MECHANICALS

I tried to mount the rings on the dovetail that came with my Apogee HD and they didn't fit. I paused for a moment, held my breath until my face turned red, then dropped to the floor and proceeded to thrash about while screaming wildly. Not to be deterred, I made a dovetail out of some 1/4" poplar and that was sufficient to hold the scope on the mount and scare me to death. So, I spent about 30 minutes grinding down the Apogee dovetail with the Dremel so the rings would fit. Yeah!

I mounted it up straight away on the Apogee HD. I tried eq mode for a while and darn near had another fit. With a heavy load of binoviewers in there, I did not like the odd twisting that was going on and was scared to death that my favorite stuff would just fall out onto the blacktop. It did not, largely because Bill was nice enough to include a clamp ring on the draw tube instead of set screws. I quickly grew tired of wrestling this beast and set the Apogee mount up in alt/az. Ahhhh, this looks familiar. Now the diagonal stayed in the same orientation all the time and my binoviewers never ended up looking straight down.

My Apogee HD is stock with a set of Celestron dual drives. No mods except a hypertune by me. It is not very good with the 1278. Actually, I hate it. Settle time was about 4 seconds and precise focusing was impossible. Actually, any focusing was a lesson in frustration. I hope my big GEM doesn't wiggle like that. I didn't weigh my setup, but I had removed the finder and was using the binoviewers. Maybe 16 lbs or so.

cont'd

Attached Image:

tomhole's attachment for post 10920
Posted 11/20/2003 08:59PM #1
The focuser initially would rack out but not in. Again with the ranting and raving whilst thrashing about on the floor. Turns out, I just needed to adjust the screws a bit here and there and it was working nicely. There is some backlash that I could not get rid of but the motion is very smooth. I ended up mounting the OTA on the mount upside down. The weight of the binoviewers would cause the rack and pinion to get bogged down. This resulted in some ratchety motion. After I turned the OTA so the rack and pinion part was pointed up, the motion was good. Even with the OTA vertical and all that stuff hanging off of it, the focuser held up fine.

The jiggling of the mount prevented any critical evaluation of precise focusing. I am very picky about my focusers, so I will report back later after I get my custom GEM. Hopefully it won't have the shakes.

As I mentioned before, the finder is a non-starter. With the binoviewers in, it is completely unusable. So, I have nothing to report about the stock finder. I just put a Rigel on the OTA and used that.

The stock 1.25" diagonal never made it in the focuser. I used my 2" William Optics diagonal that I bought for the 1278. The WO is one nice diagonal. It held the binoviewers solidly in place during my GEM nightmare. I was very confident in the clamp rings and they held up.

OPTICALS

Haven't heard anyone mention the baffle test. I took the diagonal out and looked into the draw tube with my eye as close as I could get it. could see the entire objective with the draw tube racked all the way in and out. Looks like I got the entire 127mm working for me.

Seeing was a 1.5 out of 10. That meant no star testing. I did take a look at the diffraction rings and couldn't figure out why they all looked the same. Ahhh, no central obstruction. Transparency was very good, and most of the porch lights were out so I did a quick surf. LNEM at zenith of maybe 5ish.

I did most of my viewing with the Denk standard binoviewers, 1.37x 2" OCS and a pair of 24 Panoptics or 9mm Nagler type 6's. That gave me 57x and a 1.2 deg TFOV and 152x.

The very first thing I looked at was Mars. Oh my goodness, what the heck is all that purple? Ahhhh..... Then I focused, and most of it went away. I was still in eq mode, so I was not very happy. I took a look again later after I fixed the dovetail and went to alt/az. Ahhh, much better. I used a pair of 9mm Naglers for 152x. Mars is getting pretty small these days and the seeing was atrocious, so nothing much to report here. I may get up a bit early and take a peek at Saturn and Jupiter.

cont'd
Posted 11/21/2003 09:57AM #2
>>>My Apogee HD is stock with a set of Celestron dual drives. No mods except a hypertune by me. It is not very good with the 1278. Actually, I hate it. Settle time was about 4 seconds and precise focusing was impossible. Actually, any focusing was a lesson in frustration. I hope my big GEM doesn't wiggle like that.

Tom:

Nice report. My experience with these sorts of GEMS is that the problem is not with the mount but rather with the tripod. Make sure everything is as tight as possible, all bolts and little screws that secure the legs etc.

Then lower tripod as much as possible. With a Newtonian, one can get the tripod down low because the eyepiece is at the right end of the scope. With a refractor unfortunately, the eyepiece gets down at ground level pretty easily.

I found with my Orion 120mm F8.3 refractor on a EQ-3 mount that using a sturdy, sturdy tripod cut the vibration to essentially zero.

jon