Adam J

Guys, I am getting this sorted so no need to be concerned for me, I can take care of myself just fine. I posted this thread purely to confirm my diagnosis of the problem with experts in the community so that I did not waist time and money returning a scope unnecessarily. As such this thread should not be miss interpreted as a complaint, or even an attempt to get FLOs attention via the forum, though I am grateful for their assistance here. I would rather not get this thread locked / removed as it would be nice to share the resolution with everyone and this can be preserved as an example of pinched optics in an Esprit scope for future reference. A trawl though Astrobin shows that this is not a common problem with the Esprit line but its not totally unique either and the Hexagonal shape being different from the triangle normally associated with pinched optics probably means people don't correctly diagnose the issue. thanks everyone. Adam

Really? Both of them?

Ok just posting this now for interest as if there was any doubt that the stars are hexagonal take a look at what they look like when I combine LRGB as opposed to just Lum, not much data but I think its still very telling: First this red star, I think that the shape is much clearer here: But the real nail in the coffin is this, I see 6 x while dots in the star halo: Full LRGB image here, like I say not much data at all but its sufficient to show the issue: Adam

Thanks for giving me some options Steve I am considering them, ill let you know what I want to do by Monday. Thanks for the suggestion but fortunately I know better lol. I would not touch the colimation screws on a triplet with a barge pole. The tolerances are incredibly fine. It is worth remembering that if anyone is at fault its Skywatcher not FLO and that pinched optics can only show themselves at certain temperatures I doubt ES's optical bench is in a fridge freezer. In the end though I still think the Esprit 100 is the scope for me, looking at other peoples results I have just had some bad luck. Adam

Steve, thanks I did not see Ian had replied on Friday night but had not gotten back to him yet as I figured it was the weekend and you guys would not get my reply until Monday anyway, Ill get back in touch with him. Yes I did get the ES check and tune service with the scope. I do think the optics are showing signs of being slightly pinched and a few people here seem to agree? Although to be fair to ES pinched optics can often be temperature dependent. In itself that does make me worry though as depending on temperature it may or may not show up if he looks at it again. Yes I purchased from FLO because of their reputation and if it was some other shops I would be much more worried right now, not that I aren't worried. Guess I am left feeling more than a little down about it though as this was a major purchase for me and I was very much looking forward to using it over my Christmas leave. Adam

Probably not enough pixels sampling the smaller stars to see it. I am sure they will I just don't want to waste their time over nothing. So thought I would get opinions first.

I received a Esprit 100 from FLO a few weeks back and have just this week managed to take some test images. I am thinking that this looks like pinched optics. Star Halos are looking Hexagonal to my eye, the Esprit 100 has 6 lens adjustment screws for each lens element, so more than the usual 3 and hence I assume this is resulting in hexagonal stars when pinched as opposed to triangular. Here is a close up on a star using my scope in with a UV/IR filter and an ASI1600MM Pro. I would say it was not that cold and the dew heater was running. Here is a star from my friends Esprit 100 also using a ASI1600mm pro (exactly the same image scale). More integration mind you. Here is the full test image: I would appreciate opinions on this and if I should be returning the scope on this basis. But its not the only problem with the scope, the focuser is also giving me issues as the tension is not consistent over the entire length of its movement and when delivered was so poorly adjusted that you could feel it wiggling at one end of its travel due to the pinion not engaging with the rack while at the other end of its travel it seemed fine. I managed to adjust it so its not too bad but it is less than ideal as i cant tighten it as much as i would like without it becoming too tight at one end. On the focuser FLO have agreed to return it and have a look at the focuser it. But it would be good to confirm if people think that there is a problem with the optics too before I send it as I have not discussed that issue with them yet. Originally I had tilt but that seems to have vanished now without me changing anything, just the scope sat in the obsy un touched between two sessions, so no idea what to think about that. I feel I should note that I did opt to have the scope checked and tuned by ES Reed. thanks Adam

The later models don't come with that canister. The dropped it for V3 and Pro models. Its now sealed on the inside under the screw with a thin plastic film. I dont know why they did not just remove it. Probably kept it just in case or because they have huge stocks of that design and eventually they will remove it.

That is quite a saga, hope it gets fixed. For the record I would not have found it acceptable.

Hi all, This is just a little commentary on my recent desiccant change on my ASI1600MM PRO. About three weeks back I started to notice a dark area in the centre of my images. Some experimentation showed that the size of this dark disk increased with deeper cooling and vanished with cooling turned off. I put this down to moisture in the sensor chamber. I did some research on changing the desiccant but was not able to readily find a link to the instructions on ZWOs main page. The camera instructions themselves are useless in this regard and barely mention maintenance at all. What is given talked about the original V1 version of the camera and describes the threaded front plate. I contacted FLO and they linked this document to me: https://astronomy-imaging-camera.com/manuals/How_to_clean_ASI_camera_and_redry_the_desiccant.pdf Note: That this still pictures the V1 camera and not the PRO. The main issue I have with this is that on the PRO there is a black plug on the side of the camera and under that plug there is a screw head, for all the world it looks like it might contain the desiccant as would be the case on a ATIK 400 series camera. IT DOES NOT! A reply on the ZWO forum is the only reference to this and it says that this is not designed to be removed by the user and that is why it has a black plug over it. SO DO NOT REMOVE IT. In fact the desiccant on the ASI1600MM Pro is actually accessed by removing the entire front of the camera exactly the same as with the V1 but by removing the four silver hex head screws as opposed to twisting it off. On removing the front of the camera you will find that the desiccant is not located next to the PCB / Sensor board as per the ZWO link above but instead on the reverse side of the camera front that you just removed, that confused me for a couple of seconds until i turned the front over in my hand. The problem with this system as opposed to the ATIK system is that in removing the front of the camera there is ample opportunity to introduce dust. I took three steps to minimise this possibility. 1) While its cheapest to re-charge the desiccant in the microwave the camera is open while you are doing this. So to reduce the amount of time that the camera was unsealed I decided to purchase a second set from FLO: https://www.firstlightoptics.com/zwo-accessories/zwo-desiccant-tablets-for-cooled-cameras.html. this allowed me to rapidly change the desiccant over without having to wait for it to re-charge. It also means that I have a second set to perform this switch again in the future. 2) I used latex gloves to prevent my finger accidentally touching the sensor or the inside of the sensor window during this process. 3) I placed the open body of the camera within a plastic freezer bag while I was working on the lid with the desiccant attached. All four tablets just pull out and are held in place by friction only. Following the switch over of the desiccant I gave the inner surface of the sensor window a quick blow with a rocket blower and then I replaced the camera front making sure that the rubber seal was correctly seated and that the front was orientated in the same way as when I originally removed it. These two actions prevent damage to the seal and mitigate the effects of any imperfection in the seal caused by their initial mating. I then left it in its case for a couple of days to allow the new desiccant to work and fired it up. No more problems! Hope this helps anyone who needs to perform the same task. Adam

Its not something that concerns me very much. Its that shape because that is the shape that Sony made, these sensors are not intended for astronomy, we just get what we are given. This exact sensor is designed for use in 360-degree video cameras and so its a very efficient shape for that application. Yes for M31 you would like a different aspect ratio ideally, but that is one target and I would never base my choice of camera on one target. The image will not be stretched into the monitor corners. You will end up having space either side, but then after processing and cropping and doing mosaics it hardly ever fits the monitors aspect ratio perfectly anyway. Adam

You are unlikely to get much better than 0.8" RMS with a basic EQ6 its mostly about the build quality of the gearing etc and less about the load bearing capacity. If it was me and I wanted a more accurate mount I would be looking at something like an more modern AZ-EQ6 GT or a CEM60. Adam

The main thing I take from this is that it is possible to guide a WO FLT110 on a HEQ5 pro. Just need more integration now, but a great start. Adam

SW ED80DS-Pro is 500mm once reduced. A 80mm F6 triplet such as a Starwave 80 EDT will give you 480 As you want a wider field I am assuming this is to image diffuse nebula, that being the case then 2.29 is perfectly acceptable, you would barely notice any difference between 2.0 and 2.29 if you could detect the difference at all. Adam

Nice OIII data and I like the image in general but I guess I do wonder if there is much separation between Ha and NII in terms of where the signal is placed. I always imagined that the NII filter would perform at its best against a SN remnant / planetary nebula. In those targets you get very well defined separation between filters, more so that diffuse nebula.

I would be interested in seeing the individual channels as I have not seen many NII images and its hard to see where the NII is split spatially from the HA given only the combined image. Adam

Oh i never remove them as such, they tend to go back in as they came out, it just makes processing the nebula easier.

Have you tried using starnet++ to help deal with the stars / nebula balance?

I have owned an esprit 100 for 3 weeks now but not had a chance to mount it up in the obsy yet, getting a little nervous ill get first light it will have an issue and ill be too late to return it.

I really like the color you got here. I have struggled to settle on a pallet for my Bi-color effort.

It might be possible to train an AI to make the correction as is the case with Starnet++ but to be honest that would not solve the issue of distortion to the background DSO.

Yes, the Altair version of the ASI1600mm pro will need larger filters than the ASI model due to the longer sensor back focus, the ASI can use 1.25inch filters you will need at least 31mm filters with the Altair and possibly 36mm filters at faster f-ratios. Hence you may lose any cost benefit in the camera by having to purchase more expensive filters. Don't make the mistake of thinking that 1.25 inch = 31mm either. One measurement is clear aperture the other to the actual thread on the filter holder, the 31mm are larger. Adam

Look up micro lens diffraction pattern for the ASI1600mm pro before you make your final choice. However, don't agonise too much as either one will provide good results. Adam

Its not an easy choice in this price space for OSC right now but I do like the look of these new sensors and am sure it will work very well with the ZS61, congratulations! let us all know how it performs. Adam

Don't panic.