Every time when I chase the darkness in southern lands, I try to capture some deep space objects in the southern hemisphere, which are not visible from Central Europe. One of these objects is the Sculptor Galaxy, which can be found, surprisingly, in the constellation Sculptor (south from Aquarius). Here are some features: it is approximately 11 million light-years away from us, it has roughly 90 000 light-years in diameter (similar to Milky Way) and it is characteristic by the intense star formation. This galaxy is sometimes called Silver Coin or Silver Dollar Galaxy, but I pushed the colors into the yellow spectra, therefore it looks like a gold coin.
| Telescope | Newton 150/600 mm |
| Aperture | 150 mm |
| Focal length | 570 mm |
| Mount | Rainbow Astro RST 135 |
| Autoguiding | ZWO 174MM, Guidescope 30 mm |
| Camera | ZWO 071 Pro @-0°C |
| Corrector | TS MaxField |
| Filters | No |
| Exposure | 127x180s, Gain 94, bin 1x1, |
| Date | 2020-09-21 |
Hi Jakub,
Great site with amazing photos. I just got into Newtonians and bought my first reflector TS UNC 6″ with maxfield corrector. I managed to get the scope collimated decently. However I’ve noticed blurred stars towards to bottom left corner. I suspect this could be due to tilt of CC tighten with 3 screws to Crayford focuser. I am wondering how you centered CC? Do you use auto center rings?
Thanks in advance for your response
Michal
Hi Michal, I use FeatherTouch focuser, which has quite narrow tolerance, therefore there is a very small play between the corrector and the focuser. Moreover, it has only two screws, which push the CC towards the tube. You should first determine if you have an optical tilt or a sensor tilt. Just simply rotate the camera by 180° and take a picture. Compare it with the original position of the camera. If the deformed stars stay in the same corner, you have a sensor tilt. If the deformed stars move to the opposite corner, you have a tilt in the optical system. You can find a detailed description on ZWO page here.
Thank you for your help. I’ve fixed the tilt !
My 6″ newtonian is sitting on RST-135. The imagining scale 1.3 px and I am having some challenges with guiding which results in eccentricity ranging from .5 -.7. I use ASI 290 paired with 60/240 guidescope. Recently I started using multistar guiding which improved my RMS ( 0.7 – 1.0) but it did not really made stars more rounded. Would you mind sharing RMS you were getting with this mount? Did you use PHD for guiding? What were your guiding parameters? Thanks
Dear Michal, I use RST-135 as a travel mount, which means not that frequently. I use PHD single star for the guiding (I haven’t tested multi-star guiding yet), but unfortunately, I don’t have any logs of the tracking and RMS. Normally, I set the guiding to 0.5 s, which is a value recommended by many other users. The rest I leave on default values. How do you set the polar alignment? I have PoleMaster and I am very happy with it. How long are your exposures? I tried once with off-axis guiding with RST-135 and the results were excellent. The whole stack of 50+ images was perfectly aligned, whereas when I use small 30 mm guiding scope, usually I have to crop it by 5 – 10 pixels because there is some drift/flexure between the first frame and the last one. On the other hand, it’s more difficult to find the guiding star. What target are you trying to capture? You know, the seeing is different close to the horizon compared to one completely above you.