Re: IEXOS-100 First Light report and a few thoughts/complaints #iEXOS-100

brian skinner

Hi Craig, if you have a limited sky view like me, turn autoalign off, select 2 or 3 star alignment and then go to the catalogue page when you will be invited to select the first alignment star of your choice. When aligned go back to the catalogue page and select your next star and then your good to go....
Kind regards, Brian 

On Mon, 6 May 2019 21:17 Craig Bobchin <cbobchin@... wrote:

I've received my IEXOS-100 last week and had a chance to test it on Sat. Night for a couple of hours, and I've got a few thoughts and complaints about the mount.

As background, I'm no newbie to EQ mounts, or imaging as I've had a Losmandy G-11 for about 15 years now and have done quite a bit of imaging through it. My purpose in getting the IEXOS-100 is as a portable mount to take to dark sites to do (hopefully unguided) dslr imaging with a FF camera and variety of DSLR lenses (zooms and primes).

A few months ago I picked up a Skywatcher AZ-Gti to hopefully allow this, but I was unable to get even 30 second exposures  with a 100mm lens unguided without getting trailing. The mount works fine for visual work with an 80mm f/6.5 APO in both Alt-Az and EQ mode, but for unguided imaging it's useless. Hence the IEXOS-100.

So un-boxing and set up went well, and the mount is a lot heavier than I expected.  The Az-GTi is 10lbs complete (Head, Tripod/Wedge, and counterweight.) the IEXOS-100 head is almost that heavy. I'm not sure how far I could hike with this and the camera gear, not to mention how I'd pack it all into a camera backpack. It might not meet my portability requirements, but I'm still considering that aspect separately.

I noticed after the mount was attached to the tripod that it still rotated within the tripod mounting no matter how much I tightened the bolt on the bottom. This is my first concern, in that it won't be steady enough for imaging. I might put some felt or something to give a bit of friction there.

My biggest complaint is that I had to purchase a tablet to use the mount as I intend to. I plan on taking this to the field where I will have limited power and don't want to haul a laptop etc.. If there was a phone version of the ExploreStars app that would be ideal, but the app won't work with either my LG V10 (which I use for the Skywatcher mount) or my LG V30. This is an additional cost that I wasn't anticipating and am not thrilled about.

Alignment: First off the polar alignment bore tunnel is less than useless for my 55 year old eyes. perhaps a younger set would enable me to see Polaris through it, but I don't know. I tried shining a green laser through it, but there was no way of ensuring the laser was actually square to the tube. In the end I simply put Polaris in the center of my 16x magnified live view on the camera's LCD screen. Not ideal, but it kind of worked. Just a side note, the Az-GTi suffers the same problem of trying to get polar alignment in EQ mode, and it doesn't even have a polar bore tunnel. This mount just begs for a PA scope in the bore tunnel, as I'd be out in the field with no laptop using the Polemaster is not an option for me (I've got the Polemaster for my G-11 and believe it or not, I get better PA with the Losmandy polar scope than the Polemaster.). Another option is some form of Polar alignment correction/drift alignment tool in the app (Skywatcher has this in the Synscan app.).

The ES app is okay, once you get used to it, but could stand a lot of improvement from a UI/UX perspective. It took me a lot of hunting around to figure out how to select my own alignment stars as I have an obstructed view from my light polluted back yard. One thing I couldn't find is a way to sync on an object that is not part of the alignment process. Is there such an animal in the app? If so where? It would also be nice to be able to use SkySafari to control the mount. 

Now on to the actual experience of using the mount once it was as aligned as I could get it. I was able to balance my Pentax K-1 and FA* 300mm f/4.5 using the two counterweights and a bunch of steel washers sandwiched between them.  My system for this test was about 2kg (4.75 lbs) in weight  For a mount that has a capacity of 15lbs, 2kg is not enough to balance the camera/lens combo and more counterweights are necessary, and I'm not sure where to get them. Considering I want to use a Camera/Lens combo that weighs in at 7.5lbs (3.5kg) that's a fair amount of counterweights.

The mount has a very pleasant hum when slewing and put the alignment stars pretty close to center of the F.O.V. of the unmagnified live view. A slight adjustment to center them at 16x was all that was needed. Strangely enough, this off-center alignment did not seem to improve as I added more alignment stars (I used three stars for alignment Dubhe, Mizar/Alcor, and Arcturus). I slewed to M3 as my target to try and image it. At one minute I had some trailing, at 30 sec none was visible in a 300mm lens. This was leaps and bounds above the AZ-GTi, which can't track a 30 sec image with a 3lb (1.3kg) payload (Pentax K-1 and 100mm f/2.8 lens).

If I can get a better polar alignment, I light be able to realize my dream of a portable mount that can do 2 min unguided subs. 

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