Adam J

Yeah but you can say that about anything second hand Vs new. You can get a used 294mm for cheaper than a new 533mm....etc etc.

I don't think it's the scope. The filter is suspect in my view and if a new filter doesn't solve it maybe the coating on the sensor cover glass is defective. Definitely contact your supplier. It's actually potentially worse than what I have seen from the ASI1600mm pro on that target. On the 1600 it would be confined to only the two brightest stars and no others in that field of view.

Interesting that you are getting microlensing from a ASI2600mm?? Anyone else ever had this? Are you sure your filter is the correct way around? Adam

I have started a general discussion of mobile power solutions in the thread below. But I start by detailing my DIY power rig and as such I thought a link from DIY astronomy was also relevant. Please reply in the linked thread not this one! Cheers, Adam

Following a discussion Hijacking the HEM15 review thread I have started a dedicated thread here. The system I have made and flown with on both Easyjet and Ryan Air is detailed below: I take two of these LiFePo4 batteries: ECO-WORTHY 12V 8Ah Rechargeable LiFePO4 Lithium Iron Phosphate Battery with Over 3000 Times Deep Cycle for Fish finder,Ride on Car,Emergency Ham Radio,Burglar Alarm System,Kid Scooter,Solar Panel : Amazon.co.uk: Business, Industry & Science They are 8Ah at a nominal 12 volts for 96Wh per battery Batteries under 100Wh per pack are almost universally allowed on flights in carry on luggage. You have to be really careful, not all will allow over 100Wh while FAA regs state up to 160Wh, some will allow this, but frequently this is limited to 2 packs and in some cases they do now allow a total (for all batteries) >300Wh. So you would not be allowed to take two 160Wh batteries. This has been suggested: Celestron Lithium 13.2 Ah LiFePO4 Powertank Pro | First Light Optics But I like to keep it simple, everyone will let you take a 96Wh battery on a plane in hand luggage, you cant get tripped up by it. But honestly that aside the Celestron power tanks is £235.... Here is what I put together for £120 pounds all inclusive using two batteries of 98Wh each for a total of 196Wh and that price includes a charger....so why anyone would pay for that power tank is beyond me unless you really did not pay attention in your GCSE physics and cant wire a battery to a connector and I really doubt that applies to very many people in this hobby. This is 2x96Wh LiFePo4 batteries. The batteries each include a battery management system to prevent, overheating, over charging, over current, and over discharge internally as stock, I tested and it works. I have attached cables two each terminating in a Female XT60 connector. The batteries attach to a control box in parallel with three Male XT60 connectors. This means you get the full 192Wh without disconnecting a battery, you can also charge the batteries in parallel by connecting a charger to the third connector. The Box contains a Battery charge monitor (top green) that displays percentage charge and battery voltage. Further more it contains a 12.2 volt regulator with boost (that way you can run the battery down to 11.2volts while still maintaining 12.2volts on the output (no low voltage issues), also it can make use of any battery or power supply from 8volts to 24volts and still output 12.2volts. You could even charge while in use. It also contains a 5volt regulator that outputs to a USB A-type socket so that any USB device can also be charged / powered from the batteries and finally a switch... For me this is a vastly better solution than the celestron power tank and much much cheaper. It then all attached to a power distribution box on the scope dovetail from one output and the second output powers the mount and mini PC. Discuss: Adam

You have to be really careful, not all will allow over 100Wh and some will allow single 160Wh but not allow a total (for all batteries) over >300Wh so you would not take two 160Wh batteries. I keep it simple, everyone will let you take a 98Wh battery on a plane in hand luggage, you cant get tripped up by it. But honestly that aside the Celestron power tanks is £235....what I suggested above is £100 for two batteries of 98Wh each for a total of 196Wh and that price includes a charger why anyone would pay for that power tank is beyond me unless you really did not pay attention in your GCSE physics and cant wire a battery to a connector and I really doubt that applies to very many people in this hobby. As this has Hijacked the HEM15 thread for too long now I have made a new thread here: That way we can get back to discussing the HEM15 which I want to hear more about so please move battery discussion to the new thread. Adam

So looks like ZWO are bringing out a new cooled version of the ASI585mc and it's expected to be competitively priced as a camera to introduce more people into cooled deep sky imaging. Apparently it may land in the region of £600 pounds which really would be impressive if true.

Yes I have taken them on a Ryan Air and a easyJet flight in hand luggage without issue. In the UK they did not even look at them. But in Spain they removed them and took a look at the capacity. All good.

I just use this type of battery: https://www.amazon.co.uk/ECO-WORTHY-Rechargeable-Phosphate-Emergency-Fishfinder-8AH-Lithium-Battery/dp/B08ZSBS1ZY/ref=pd_aw_ci_mcx_mh_mcx_views_3?pd_rd_w=m2RAD&content-id=amzn1.sym.42c045e2-bd09-44b6-b445-e4140e05d91f%3Aamzn1.symc.acfafb1d-071f-4fdf-beff-aca206a47be9&pf_rd_p=42c045e2-bd09-44b6-b445-e4140e05d91f&pf_rd_r=7ADW105Z7QZ6CT4RAESY&pd_rd_wg=OYmeH&pd_rd_r=e7fab86d-47e1-4e5b-bfb3-8f9602426e0e&pd_rd_i=B08ZSBS1ZY cheep and it works really well. Sized for airline travel with a battery management system included. All you need to do is make sure the terminals are covered for air travel and also buy a suitable charger. Why pay more. Adam

Also Wipe the ENTIRE filter wheel down it will be full of spores and you want them all dead. Adam

Well for a start they are not nearly identical. I have recently seen results that show better contrast from chroma 8nm than Antlia 3nm filters. Chroma 8nm Ha, 5nm Sii/Oiii vs Antlia 3nm SHO 50mm round filters - Experienced Deep Sky Imaging - Cloudy Nights But in any case you need to get it off as it fungus can be acidic and will etch the filter coatings if you don't get it off sharpish. I would use what you have, acetone is recommended and you have some so use that, then wash it off with distilled water after that. Don't worry about little water marks for now, just get the fungus off ASAP and worry about that later. I personally use pure cotton buds to wipe the surface, the important thing it is to keep rotating the bud and use many many buds so your lifting the stain from the surface not just moving it about. Adam

Never heard of anything like that before.....very very odd. My bet is that it's something very simple that you have missed. The GT71 is actually a very simple but of kit you know. Perhaps some pictures and a sub will help people help you.

Olly is that image Duel narrow band data?

it is possible they have improved it.

Now the FRA300 has a wonderful spot diagram, one of the few scopes that by claim at least would make use of 2.3um pixel cameras. Adam

Vlaiv is correct they are intrinsically connected. OP is making an argument that 200mm aperture will resolve more than a 85mm refractor..am not so sure that true, I would say that for most of Europe unless you are at significant elevation both will resolve the same due to atmospherics but if you did take the RASA up the mountain your not going to get close to 0.58 from its optics. Image quality is also about Signal to Noise as you cant get details with poor signal to noise to the RASA images will help in this case but the problem is that there is a point when more Signal to noise will no longer gain you detail. So it depends on the target. Adam

Fitting the filter draw in for a start but yes no filter wheel. But I could also add off diffraction spikes form leads and not being even close to diffraction limited performance to that list.

I can honestly and whole heartedly say i would personally not buy either scope. The flat field on the 85 is disappointing for a scope of its cost and the F2 RASA has always seemed like too much compromise in other areas (filters, difficulty using mono). If spending that kind of money and wanted to be at 400mm focal length I would 100% without a doubt go with an Epsilon 130, no problems with filters and no problems with mono. Adam

Its actually hardly ever tilt causing bad corners from what i see, its just the go to explanation, its much more often a problem with collimation a problem would normally result in the OTA being returned or tweaked. I can just see it that in the future when you get a new refractor with collimation problems the manufacturer will just say why don't you just use BXT.... The above looks more like an optical issue than a tilt issue to me. I would be doing a star test not "fixing it" with BXT. If an out of focus star test in centre field shows non concentric rings...I think it will, then it needs colimating as something has shifted in transport. Not sure if the cells on these are user colimatable. So maybe ask the supplier if this turns out to be the case. As its showing on the short side of the sensor then its also possible to rotate the camera 90 degrees, if it stays the same its tilt, if gets mush worse its colimation. It has its place as you say, but even a budget refractor should come well colmiated even if the polish / correction is not top notch and while fixing minor issues is great you should not convince yourself to accept less than what you paid for.

We spent time making sure our optics worked correctly...some of us still do as BXT cant generate detail out of thin air.

Many thanks, how about peak errors?

it will be great to see some guide results. Be good to see a calibration plot too. Not sure you get that plot though on an ASI Air?

Hypothetically how much would it cost me lol

The rate of tech improvement in sensors is actually not as steep as some make out. After all you can only make things so good before [removed word] noise and LP are the limitations. As a result these older sensors are often underrated by the community. Someone who knows what they are doing with such a camera will put image someone with a new 2600mm used by an inexperienced imager.

Could be so many things and you have not provided much information, most likely is your not well polar aligned. Can we at least see a sub frame?