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Hi I have just purchased a new GT81 and I am having trouble getting focus. If I use a 1 1/4" diagonal and 1 1/4" eyepiece, I cannot reach focus at all. If I use a 2" diagonal and 1 1/4" eyepiece, I can only just reach focus. If I directly attach a DSLR or ATIK CCD camera I cannot reach focus. My only option to do astro-photography is to add a 2" extension tube, but even then I am at position 7.5 out of 8. In this I am concerned about flex using an extension tube when I use a DSLR or worse still when I use an ATIK CCD and Filter wheel attached. Is this all to be expected ? I have also ordered the Field Flattener but it has not arrived yet. Will it be easier or harder with the FF ? Rodger
Hi can anyone help "PLEASE" I recently found my lens cell on my GT81 was dirty and having Badder wonder fluid and the correct clothes, I attempted a clean on both sides of the cell. Doing everything correctly I find now I have an oily smear on the inside lens. Panicking I spoke to SC Telescopes who advised I hadn't damaged the coatings and that using the soft disposable J cloth type and breathing on the lens I should be able to remove the smears. I have tried this and it isn't working. I would like to get it properly assess and professionally cleaned as I've cocked it up and want the job done correct ( and hopefully I haven't damaged the objectives) Can anyone recommend a company that offer the service. If local to the midlands I can drop the lens cell over and collect, failing that all I'd need to do is send the cell by recorded delivery and well wrapped and insulated against travel damage. Thanks Allan
This is my first data set for the heart nebula in HA. Processed it a bit in Pixinsight and finished it off in Photoshop with some pointers on sharpening. May have overdone it a tad bit but i am pretty pleased with the short amount of data the detail i have been able to coax out of it. I had planned on 5 hours of data but only got 2 hours 40 mins of 20 min subs thanks to incoming clouds. I'll take what i can get lately.8x20 min subs with dark and bias calib files
I just had to show it off; I'd rather be outside looking through it, but too cloudy. First impressions are pretty darn good. It's a beautiful instrument, the fit and finish are superb. This is the 20th Anniversary Edition GT81 f/5.9 81mm APO refractor from William Optics. It has a two speed Crayford 2" focuser, with a 1.25" adapter. It comes with a small "shoe"-like dovetail bar, and a carry handle that also mounts a set of rings large enough to hold a 9x50 finderscope or guide scope. Just to see how it looks, I installed the 9x50 finder from my Edge 8", and will probably leave it on the frac, since I rarely use it on the SCT. The dovetail bar is barely long enough for the two large tightening screws on my AVX mount to grasp, there is no room to move the OTA forward or back on the mount to assist in balancing once all the accessories are attached. It is threaded so a longer dovetail bar can be attached. The telescope is only 17" long with the dew shield retracted, and weighs around 8 pounds. It comes with a soft case with a fitted closed-cell insert, and the William Optics logo is nicely embroidered on the cover. I also purchased the field flattener/reducer for this scope, it makes it a f/4.7 when used, and so far as I can tell, the reducer is for AP only, it comes with an adapter ring for a Canon T-mount, which can be unscrewed; the threads are then correct for a Nikon T-mount, but there is no means to place an eyepiece in the reducer. The reducer is threaded on the end that inserts into the 2" focuser barrel along the last few mm, but it has a broad sleeve with the safety recess that fits very snugly in the focuser tube. With the three thumbscrews snugged against the brass collar inside the focuser, there is absolutely no free play to be had. Very solid. I also tried a variety of my EP's and accessories, they all fit well and without any movement once tightened. I can't wait for a nice, clear night to try out this marvel. I have a side-by-side dovetail bar coming so I can mount this alongside my Edge.
Bit disappointed with the focuser on my recent addition to the fold so far. Just wondering if other owners have any had the same issues or if I've a bad 'un. The focuser seems to be unable to take the weight of a CCD & FW without becoming way looser in comparison to my ZS71 which has practically the same focuser and went through an entire season without needing any attention with the same load. It seems the small grub screws require tightening right up therefore leaving the rotator unusable and even then the tube still has flex in it. The focus point is almost at the end of the drawtube travel so that doesn't help either. Before re tighten http://youtu.be/zqCFKq53sYg After re tighten http://youtu.be/eVtdFGP52ik