tomato

While listening to last night's excellent StarGazine talk I collected 4 hours of LRGB data for this image, a bit optimistic given a 50% illuminated moon, but beggars can't be choosers etc. I combined this with some earlier data which suffered from poor sky transparency and a large dust artefact on the Lum camera. I wasn't prepared to throw this away however, as I Iike to see how many more distant galaxies can come through on the image with the additional integration time. There are lots in this region, most not picked up by PI's image annotation script. And yes, I am aware that NGC 3729 is just out of shot, but to include this I would have to have rotated the cameras, and I didn't want to spend an hour doing this and miss Ivo's talk! 7.65 hrs total integration time L 75 x 3 mins RGB 26 x 3 mins each Esprit 150/ASI 178 dual rig, all data binned 2x2 Thanks for looking

I use ASI 178 mono cameras on an Esprit 150 exclusively for small galaxy or tight galaxy cluster imaging, as the FOV with this setup is only 0.4 x 0.27 degrees, usually binned 2x2 unless the seeing and guiding are exceptional. They have significant amp glow on extended exposures (> 2 mins) but this calibrates out OK. They are retro-fitted with Peltier coolers which maintain them at a constant 3 deg C to assist with calibration.

Excellent talk, Startools is a bit different, but it suits my approach to imaging down to the ground.

Thanks Martin, The hair was substantial enough to have some colour, namely white. How did it appear after several weeks in a sealed system, I guess it wafted down from the Lum filter. I have one of those little camera lens bellows which I use when assembling, I may need to invest in something more substantial.

I've seen the Saturn V at the Cape, once in 1988 when it was still outside and suffering in the Florida climate and again in 2005 when thanks to everyone's donations it was resplendent in it's own hanger. Jeff Bezos spent some of his pocket money finding and recovering some of the stage one engines from the bottom of the Atlantic, I believe they found one of the Apollo 11 engines after checking the serial numbers, I think some of them are on display at the Museum of Flight in Seattle.

Love those F1 engines at full chat, hope to see the recovered ones from the Apollo era someday, are they in the Smithsonian?

If you have PHD open during the calibration, it will give you information about the process in the bottom left hand corner. It should take about 10-30 steps and you can see the star being brought back to the centre when it moves in the opposite direction. Given the problem you had I would definitely recommend you do a calibration at the start of the session, if it successfully calibrates that rules out any initial set up problems.

No worries, I’m too far North for the delights of the Galactic centre, and galaxy imagers have the ‘dreaded moon’ to contend with every month. But like I say, there is something up there for everyone.

I have just added up my images captured since August 2020, 15 in total and that includes a 24 hr mosaic project, but obviously having a dual rig helps. If you want to intensify your image capture I thoroughly recommend a “fast” scope like the RASA and one of the latest sensitive CMOS OSC cameras. Just look at @gorann’s results from a dark location to see what can be achieved with integration hourly totals still in single figures, and at the other extreme, reasonable results can be obtained on some NB objects when the moon is out in about an hour. ‘Dreaded galaxy season’? My favourite time of the year mate! Plenty of choice up there for all tastes.👍

Quite an imposing title for the talk, sounds more in keeping with PI. I’ll be there.

Here is 7.2 hours on NGC 4051, an intermediate spiral galaxy in Ursa Major, discovered by Sir John Herschel in 1788. It is around 45 million light years distant and (it says here) has a super massive black hole at it's centre of 1.73 million solar masses. The image is rather spoilt by a large hair on the Lum camera sensor which created a big shadow to the top right of the galaxy, which I think caused the diffraction spikes on the star in this region, based on the observation that the spikes disappeared if I moved the star out of this region. The hair has now been removed, after spoiling another image. I was too lazy in assuming the flats would take care of it, lesson learned, I will be more vigilant on sensor cleanliness in future. Details Dual Esprit 150/ASI 178 cameras binned 2x2. L 73 x 3 mins R 24 x 3 mins G 25 x 3 mins B 22 x 3 mins Calibrated and stacked in APP, processed in APP, AP and Gimp. Thanks for looking

Great start! I have about 4 hrs of LRGB data on this target, it is coming out a silvery blue on the initial stack but after doing a star colour calibration in APP the galaxy has indeed acquired a golden hue. It certainly has an intriguing appearance, the dust lanes look almost artificial, too 'clean'. Unfortunately I had a substantial dust doughnut on the Lum camera which I thought would calibrate out but flats do have a limit to what they can clean up so I think I need to take the lum data again.

I have a Velcro wrap around the camera to help secure the lead but it is a bit iffy. But could a loose usb plug create a low signal scenario from the camera?

I have a OAG with an ASI 120 mini guide cam running PHD2 with synchronised guiding using NINA. The other night the SNR value went from 270+ to 14 in about a second, PHD reported star mass change and the guide image looked like cloud had come over. However the scopes were pointing through the aperture and the sky was clear. I stopped guiding, disconnected and reconnected the camera and all was OK. Last night it did the same thing again about 10 mins apart but fine after that. Note the camera is not losing connection, so it is not a dodgy USB lead, it is as if the signal being detected is being massively reduced. The only other thing I noted was it happened just before or after a dither operation. Any thoughts?

Yes, great detail for 30 mins of data. Sky transparency was great last night, when there were no clouds in the way.

Absolutely stunning images, I confess I prefer the stars to be present in images, but you have done a superb job in seamlessly removing them.👍

My understanding is that the read noise on CMOS sensors is not as repeatable on very short exposures when compared to CCDs hence the use of flat darks rather than bias frames with CMOS cameras. However, I confess I’ve never tried bias frames with CMOS cameras so can’t comment on the difference from first hand experience, and the latest generation of CMOS cameras have very little read noise anyway.

Welcome to SGL, I think you have a well thought out approach to imaging, it is tempting to go for the high end stuff before maximising what you can do with your existing kit, the former is the route I took, but fortunately I do now have the time (if not the clear nights) to try and get my skill level to catch up. +1 for the Star Adventurer, the ability to image relatively easily from a dark site can really boost the quality of the images captured and thereby maintain your enthusiasm for this hobby. Clear Skies

Got 90 mins of half decent subs despite a bit of a gale blowing, one advantage of a dome, especially if your target is on the leeward side.

I have access to two 150s, one purchased new in 2018 with the ES Reid inspection, the other second hand (but as new) in 2019 without the inspection. To my untrained eye they look Ok even at sub zero temperatures, the scopes are housed in an unheated observatory, not sure if this is a factor. Hope your replacement performs, I could only dream of a dual APO rig of this aperture without these SW scopes.

A very classy whirlpool, not many unguided images can take a crop like this.👍

A wonderful image, you have done a great job with the PI mosaic scripts. Don't worry about pixel peeping, this is panorama to be enjoyed at full scale.

Thanks, I forgot to mention that I am binning the sensors 2x2, so I am imaging at 0.94 arcsec/pixel.

Thanks Martin, the background is a little messy due to a humungous dust bunny on the Lum camera. It was clearly evident on the flats but was not fully calibrated out by APP for some reason. I am finally beginning to realise that data is king, I thought my large aperture dual rig could cut some corners, but on these kind of targets I need to be in double figures on the integration hours.

+1 for a powered shutter and detector for rain protection, especially in the UK. If I am in the adjacent warm room and here rain on my tin roof I can get out and close the shutter quick enough, but not if I have retired to the living room and monitoring via TeamViewer or something similar. Also I have seen perfectly good subs being collected and rain lashing in through the open aperture, such are the vagaries of the British Weather.