Rusted

Sorry. I meant to get back to you on this but wanted to confirm first whether the new ZWO driver download had helped my cause. The trouble is I'm fighting cloud. Which doesn't offer any opportunity to capture anything at all! I'm on full gain and peering through the clouds!

I have always been a martyr to telescope envy. Fullerscopes was offering virtual reality long before the <cough> "real thing" came along. They should have sold raffle ticket to "wishful thinkers."

Thanks Mark. Here are two more later shots: Completely clouded over now.

If you have the H-a gear then get it in gear.

The sun always shines on SolarChat!

Thanks Freddie. Swapping cables had no effect. Not even thought about drivers. Until now. I'll be back.

Thanks again Freddie. I was imagining having to do a dark and a flat for every single capture. Rod operated, flip-top, hinged objective lids, with a dark cap and a flat screen were being examined as the next project. I believe Alexandra has mentioned having very similar noise problems with her own ZWO ASI174. She reports that other manufacturer's versions, using the same chip, do not exhibit such noise. Basler, et al. My ZWO ASI174MM has developed noise and a coarse grain over time. It now shows up on lunar captures as well in very cool conditions. Making it worthless for that purpose. When I first used it on the Moon it could capture Plato craterlets. Not any more! One dealer wants me to send him examples of my affected images on the ZWO ASI120MC. These will be forwarded to ZWO and then a return address provided once the fault has been diagnosed. This sounds very time consuming! The ASI174 came from a well known, UK dealer. I have not contacted them yet. I was hoping to find a workable solution here first. To avoid losing what fills all my days and months in isolation. With two ZWOs cameras now all but useless I should be looking for a far more productive [and far cheaper] hobby! I have huge amounts of time and effort invested in building my observatory and its equipment. Not to mention the considerable expense. Fortunately it was hugely rewarding. Until now.

Interesting response. Thanks. Can you explain these "errors" please? You are obviously doing something right to have obtained these very even images. I have only just begun to use flats for my own PST etalon based 150mm/10 H-a imaging. I swap regularly between a BF5 and a LUNT 12mm BF. Choosing the one which works best on the subject. Though I use SharpCap, AS!3, ImPPG and PF7m, I have found flats rather "high maintenance" but beneficial. Your own telescope build and processing experience might hold valuable information for us all. Thanks again

Thanks Richard. No. I have heard of it but not dabbled. A free option would be good to get a feel for what is possible. I am searching around the subject to see what is available. I shall try darks first.

Thank you Michael. If only it were that simple reaching the objective to cap it. I have been practising with flats with a hat-like cell. Now I need to add capping to my repertoire. A small, 18" high, stepladder has already been added to the observatory furniture so I can reach for flats. A daft question: Can the darks be captured after the lights and flats? I don't want to lose the small region of interest when dealing with a 3m focal length and small frame size. I may be misunderstanding the required order. If there is a fixed one. Flats require a change of gain or exposure which then have to be returned to the lights settings. It would be so much easier to capture the lights first. Followed by the darks and flats. Then it won't matter if the telescope is disturbed slightly by the capping and/or fitting and removing the flat cell on tip-toe. Moving the telescope is very undesirable when capturing a prom if it requires re-centring the ROI. Made worse by SharpCap covering half of the capture screen.

Thank you Michael. Perhaps you would be kind enough to explain how I "look at the darks?" There seems to be an option in SharpCap under Capture. I use this for "flats" but haven't yet delved into the murky world of "darks." [Until now!] Well, I just captured a "dark." The file opens in Gimp. With which I have zero experience. All I see is a plain black rectangle. Must the "dark" be captured at the same time as the image video and the flat? Perhaps to ensure the camera is at the same temperature for both? I'd better do some online homework on this "dark" matter before I break something! An UPDATE: Here is an excellent description of darks particularly related to SharpCap: Capturing and Using Dark Frames

Hi, My ASI174MM has reached 43C. It shows in the snow. The coloured image is after ImPPG has almost rescued it. The B&W is a screen capture from AS!3's window. The noise is horrendous! The third image captured a lucky bit of steadier seeing. Note the rippled background over which the image seems to be "projected."

Good detail but now you need to try applying flats during capture to remove the artificial sunspots.

Good effort and nicely presented!

Hi Alexandra. You must be psychic. I was just about to post these two images captured at 41C and 31C according to SharpCap. The ASI174 was cooled off in the fridge between snapping these two still images in SharpCap. Cropped and enlarged in PhotoFiltre. I think the difference is clear. ASI174 + Heat = NOISE! Whoops! I seem to have messed up the enlargement judging by the arc of the limb. I'll be back later with a better match for scale. I am still trying to work out why AS!3 automatically sharpens my AVIs when no sharpening is selected. When I open the resulting images from AS!3 in ImPPG they are already showing hideously coarse grain even at the default settings.

Thanks Ken. Some more images from this afternoon Captured during a lull in the agitated seeing, for you to ponder over: The first is unsharpened. The second was given one touch of sharpening in PhotoFiltre. At a glance it look sharper. In close-up it is all grain. Which is why I never sharpen.

I have captured a flat pointing at the sky using my 90mm f/11 with 2.6x GPC and completely out of focus. Captured in SharpCap [no binning] run through AS!3 as an AVI. No sharpening. No obvious artifacts.

Aha! I shall see what I can do. I'll be back. Here are two images I captured this morning: The first is ugly but the second is better. Though still coarse and grainy.

Thanks. I have not knowingly added binning but will double check. Fortunately I have just made a "flat" screen and have been using it on my recent images. Translucent poly bin bag over a light metal cell. It works wonders with the PST's foibles. I'm afraid I have been having a bit of a rant about the ZWO camera. I spent a lot of money on the ZWO ASI174MM. Then find myself going down exactly the same plug hole as the 120MC. My minimum focal length with my 150mm/10 is 1500mm. I often use the WO 2x Barlow for 3m. This is ideal for the ASI174. Which is why it is a popular camera in the solar imaging world with longer focal lengths. Though the smart money seems to favour the alternative 174 sensor cameras albeit at a much higher price.

I wish I could have done a much better job of it but my ZWO ASI174MM is following the ASI120MC downwards into a permanent, coarse mask overlay on every image. Almost like water droplets on plastic. Except that the droplets last all day and every day now. Which is impossible if it were really dew. I am using the equivalent of doubled Baader D-ERFs plus extra UV/IR filtration. I have checked and double checked. There is no dew anywhere on any optical surface. The camera and LUNT B1200S2 both go back indoors overnight to protect them from the overnight cold in the dome. They aren't very cold and are in sealed containers in poly bags. So no condensation occurs when brought into the warmer environment. I tried removing the protective filter [temporarily] from the ZWO ASI120MC but nothing changed. Has anyone else suffered similar symptoms? I wondered if it was electrical "noise" on the system. So removed everything except the laptop and camera. I have unplugged all PSs. Unplugged all the cables. Tried moving the cables around. Changed the camera cables to different examples. I have several of each in different lengths. The mounting is earthed to a 2m long ground rod in damp, clay soil with a 5m long x 6mm^2 cable. I went through all of this with the ZWO ASI120MC and never found a cure. Could it be the popular, capture and processing software producing permanent "grainy" artefacts over time? Why only me? I have no idea. Perhaps it is the sheer number of hours the camera is exposed to H-alpha? It certainly isn't dust or dried dew on the camera sensor or covering filter! I have deliberately avoided removing the ZWO SI174MM filter to avoid getting any dust on the sensor. The filter gets a squirt of air from a blower bulb now and then.

I've been struggling with coarse grain on my ASI174 all day! So don't kill the messenger!

Thanks Pete. I just wish I'd done it proud!

Thank you Richard. I'll keep trying. First captures after lunch:

It went from about 40% to 90% as I shivered in the dome. There's a beautiful disturbed area near the SW limb. It's not art but it's all my own work.

I'm a martyr to scrap metal! It can never resist me!