MarsG76

The bottom image is the one (first imaged taken) before the back spacing tweek... both images are imaged with exactly the same equipment... and my small filters do not help the vignetting side, but if I can achieve a perfectly flat field.. ie nail the perfect back focus than cropping out the 5% around the edges is not much of a loss. As you can see, the top image is better at the edges even though the bottom image was more severely cropped... I believe that a perfectly flat field is possible but requires a bit of trial and error... but I feel that I'm close. Theres also that tilt... although I'm suspecting the plastic shims with that problem....

I don't find it to be expensive when you consider the price of other astronomy gear.. but it improves images while "speeding" up you optics by halving the needed exposure time. But yes, a Christmas gift is a great idea.

Fantastic Mars....

I'd say that this experiment is a success...

Greetings Astronomers, After imaging a wide field of the Large Magellanic cloud at 150mm FL... ... I imaged a couple of close ups of the more interesting regions of our Satellite galaxy... the Tarantula nebula and the Dragon's Face nebula. Both of these photos are imaged with the C8 at f6.3 (Hirsch focal reducer/flattener) with a QHY268M. The first image was a SHO narrowband image of the Tarantula Nebula region, total integration time 12 hours and 35 minutes. The second image was a result of not being anywhere happy to the "flat" field quality I am getting with the FR... the stars at the edges are ugly and I have to crop a lot of the frame to have a sort of acceptable result... but even than the field curvature is obvious. When I try to research the reason, I find explanations like that the FR light path is too narrow for a true flat field with a APS-C sensor size, even when my back focus is set at around the (recommended) 105mm distance (testing the sensor further and closer didn't help)... using 1.25" filters probably isn't helping either... but I wanted to try and exhaust all possibilities before giving up... but also was not keen on losing any of the few and far between clear nights for this so I accepted that cropping it will remain for a while. A long story/short is that I had a clear night but of particularly poor seeing, so imaging was not going to result in any quality images and so that night was spent on setting up the FR in a "out of the box" kind of thinking... and on that nights 180 second test subs, the (bloated) stars were round all of the way to the edges... but thats a story for another post in the "equipment" section. I imaged the "Dragon's Face" region during the next clear night of decent seeing in HOO, total integration time of 5 hours and 10 minutes, and the stars were indeed closer to a flat field than previously, although there is still room for improvement... vignetting still has to be dealt with as flat frames don't completely remove it but the stars are still a lot better. Sorry for the novel, thanks for looking and clear skies, Mariusz

The 8SE is capable of some great images... the long focal length is a challenge but doable... I imaged with a 8SE and a astro modded Canon 40D for years... Adding a f6.3 focal reducer will get the whole moon into the frame with a APS-C sensor sized camera like the D3100. Now I'm still imaging with a 8" SCT, same spec as the 8SE and with a QHY268M, same size sensor and still happy with some of the images I can get with that setup. There was a total lunar eclipse visible from here on 8th November and the images I posted were taken with the C8, a f6.3 reducer and a unmodded stock Canon 40D... definitely doable.... the only change I did with my 8SE was to put it on a CGEM mount, but that more for long exposure DSO rather than moon photography. Controlling that focal length comes with practise and is also more effected by seeing quality. MG

I thought that it was Uranus too, but looking at Starmap Pro, it looks like Uranus was further up in the 2 o'clock direction out of the frame from my latitude... According to Astrometry.net it's a star HD18256/Al Butain II/ epsilon Ari....

Hi All, Sharing my images to add to the thousands of the latest lunar eclipse images already posted... these images were imaged at 13:15, 13:28 and 13:45UTC with a stock Canon 40D, through a C8 at f6.3. Clear Skies, MG

Awesome work.. that crazy good and some serious exposure time dedication.

Nice and tidy work Olly, well done.

Hello All, Sharing my latest imaging project which I managed to complete between life and weather... The Large Magellanic Cloud, a companion satellite galaxy of our own Milkyway galaxy, located 163,000 lightyears away, visible only from the southern hemisphere. I had to image this object at 150mm focal length to fit it into the frame because it's huge in the sky. I imaged this through a Sigma 150mm f2.8 prime lens and exposed in HaLRGB color using two cameras, a QHY268M astronomy camera for the luminance and H-Alpha signal and a stock unmodded Canon 40D DSLR for the RGB color data. The reason for using the DSLR for the RGB data was to save time, capturing all of the RGB signal simultaneously as opposed to capturing the red, green and blue subs separately through filters. The noise level and overall image quality of the RGB data was not much of a concern as long as there was color data with in the signal, as I only used it to colorise the luminance channel. Guided with an 80mm refractor at 500mm FL and tracked on a hypertuned CGEM mount for a total exposure time of 7 hours and 23 minutes. I could have used my astromodded and cooled 40D for the color but I opted for a standard camera because of weight... this setup was piggy backed off my C8 & Refractor setup, and slightly to the side, so using a 700g camera body over a 1.8kg unit made the off balance tracking more accurate at this focal length. As a added bonus, the QHY268M is a similar mass so swapping the two cameras didn't require re-balancing. Imaging a wide field image like this also helps me pick interesting targets within the galaxy for me to zoom in onto like I did with the Small Magellanic Cloud Project... ...so with the immense amount of objects within the LMC, I have quite a few targets for the C8. If you read through this whole novel of a post, thank you and clear skies... Mariusz.

Yes, but only with a transparency of 35%. This is the level I was happy with before the image started looking "over cooked".

Hi All, Sharing with you my latest image of Saturn which I'm quite happy with how it turned out with my average C8 telescope. The night when I imaged this was a particularly clear and still night which delivered views in the eyepiece that were sharp as a tack all the way up to 406X magnification... I could not let such a clear night go by without imaging and so I decided to push the telescope magnification as far as I could. I imaged this scene with my C8 SCT using a number of exposures, cameras and focal lengths. I imaged this image using my Skyris 618C at f30, and through my DMK21au618 at both f30 and f50, 10 videos 90 seconds long at 60fps (f30)/30fps (f50) by using my 3X Barlow and 5X Powermates. I also captured 10 videos through my IRPass685 filter at f30, although the signal was quite dim and the most I could run the capture at was 15fps for 2 minutes per video at maximum gain. The moons were imaged at f10, 15 fps also max gain. I processed all data separately, than scaled down the f50 image to the f30 size and "screen" combined those two images aligned images together, this has revealed a little bit more detail within Saturn that was visible individually. I used this as luminance with the Skyris 618C stack as the color data, effectively creating a LRGB image. I combined this image with the scaled up wider moon processed stack. Clear Skies, Mariusz

Welcome to SGL.

Hi All, Sharing with you what I hope is a first in a series of a collection of images. This is a close up image of one of the regions in the Small Magellanic Cloud that I planned on imaging after noticing this (and a few other objects) in my wide field image of the SMC which I exposed almost two months ago. This frame contains NGC346, NGC371 and NGC395 which I'm hoping is the first in a set of close up images of objects detected in wide field "survey like" imaging projects... in this case the Small Magellanic Cloud. There are a few more regions of interest in the SMC which I'd like to explore a bit more closely before repeating this idea on the "Large Magellanic Cloud". This image is a bi-color image which was exposed through a Celestron C8 at f6.3, 1280mm (theoretical) focal length, with a QHY268M camera and filtered with a Baader 7nm H-Alpha and OIII filters. Tracked with a hypertuned CGEM mount. Total integration time for this image was 4 hours and 10 minutes. The reason why I want to look deeper into the Magellanic Clouds and what fascinates me about the two satellite galaxies to our Milky Way is that there are a lot of strange shaped nebulae located with in them... if not looking like a chaotic spindly mess, they look like vortices... to me the shapes of the nebulae look quite alien when comparing to the more traditionally imaged and more known nebulae. PS: I said "theoretical" 1280mm focal length, because when plate solving the frame, it was solved to be 1307mm. Clear Skies, MG

Hello and welcome to SGL...