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As I said few days ago in my presentation I recently got my first scope (skywatcher 127) and over the last days I tried to test It.
Due to impossibility (temporary) to bring the scope in a decent location to make observations, I had to test it from home through a window (and under the sky of London - not the best at all). So i know that quality is of course affected.
On the other hand, I am sure that the performances are worse than I could expect also under these conditions (maybe you will correct me) and would asks for opinions to improve.
As a (mainly) planetary scope, I did not have a lot of choice: no Moon, Jupiter and Saturn out of my field of view. I pointed at Mars.
First sight, I see the very big central obstruction. I played with the knob of the focus to get rid of the big black spot in the centre of my target and here you are the issues that I would like to talk about:
1) the target became very small (ok) but still was not focus (very blurry and not a lot of clues to get atleast the shape of the planet well defined - can imagine to find any detail on it )
2) Also the colours did not convince me as no other colour than a light yellow was visible
3) Changing the eyepiece (10 instead of 25) for a magnification of 150x did not improve the situation: probably the image was even worse, more blurry with more irregular shape than before, no ability to focus at all. Differences from before : bigger (but still much smaller than expected) and very little variation in colours (I believe I saw a bit of orange).
To complete, later, I tried the scope to stars: Orion costellation was visible from my place and tried to all the stars. Although still a bit blurry (the brightest stars), I had impression of more sharp view, differentiation in colour and better shape (stars almost like a dot). Moreover, to give you a final idea, Mars (at the best focus I could get) did not appear that much bigger than Betelguese.
What do you think I can do to get better results? Could be a scope problem or some adjustments needed? Unfortunately I have no comparisons.
Thank you, Hope I was not too long 😅
I’ve just acquired the above (birthday prezzie!).
It’s a nice finder, and a definite boost from the 7x30 bundled with the scope!
However, I’m struggling to get anywhere near focus with my Pentax K50 on the end of it... anyone know why? There’s no focus mechanism to speak of, other than the objective lens’ mounting thread...
By Padraic M
I spent the full night out last night and got 6 hours of Ha lights on the Bubble and the Horsehead. Reasonably pleased with the results, but even though I followed my usual process and got good focus statistics in APT, I am slightly out of focus with roundy stars and some are even slightly donutty. Samples are attached below.
- After getting close to spot-on focus, the APT Bahtinov Aid showed a focus distance oscillating from -0.02 to +0.02. Seeing seemed good to the inexpert eye. Not so sure about transparency as there was some thin, wispy cloud throughout the night. So, I started the night's imaging with focus 'Close' rather than 'On' focus.
- Different subs show different quality stars, ranging from small donuts to circles.
- HEQ5 Pro Rowan; SW Esprit 80 with field flattener, SW stock manual Crayford focuser; ZWO EFW Mini; Baader 1.25" 3.5nm Ha filter; ZWO ASI1600MM Pro binned 1x1 @ -20c.
- AA Starwave 50mm guidescope with ZWO ASI290mm Mini guidecam binned 2x2.
- All subs are 300s, gain 139, offset 10.
- Polar alignment with Sharpcap to 17 arcsec ("Excellent"); capture with APT; guiding with Phd2. Focus with Bahtinov mask and APT Bahtinov Aid. Stacked in DSS with Darks, Flats and Dark Flats.
- Mount is well balanced in RA, but is very camera-heavy in Dec.
- PHD2 guiding was around 2"/px. Imaging pixel scale is 1.9"/px.
- Do I put the round stars down to seeing, given that the Bahtinov Aid focus distance was bouncing equally above and below zero?
- Can poor seeing cause the donut stars?
- Would an electronic auto-focuser do any better in this situation?
- Would the Seeing Monitor in Sharpcap give useful information? I didn't think to use it last night.
- Could my guiding performance, and possibly the Dec balance, have affected the image quality in this way?
- What are my options in future - abandon imaging for the night? Bin all images in software 2x2 or 4x4 to sharpen the stars at the expense of lower resolution?
- Other suggestions?
Sample 1: Detail from a single 5-min sub of Bubble nebula at 100% showing round stars, and a blurred bubble.
Sample 2: Detail from a different sub of the Bubble nebula at 400% showing donuts
Sample 3: Detail from a 5-min sub of the Horsehead nebula at 100%, showing both round and donut stars
Finally, both images stacked, calibrated and stretched, scaled to 4x4 in Gimp. 28x300s Ha on bubble, 22*300s Ha on horsehead.
Baader optical wonder solution is practically Isopropyl alcohol. Instead of £12 for a 70mL of it, buy a 1000 mL of Isopropyl alcohol for £22 (before pandemic it was only £5). They have also smaller bottles which will be cheaper of course. The Baader solution and Isopropyl alcohol don’t remove the toughest of fungi on optics, only a few of the less deep set ones can be treated with them. I have used both for cleaning eyepieces and on certain stage of cleaning several 8 to 12 inch mirrors. They both worked identical. When applied through an optical cleaning fabric, they remove ( dissolve) fatty oils and fingerprints on optical surfaces. I had cleaned a 12 inch mirror once which for some unknown reason had ice cream stain on it (cleaning followed standard operation procedure for cleaning coated aluminised mirrors).
I am excited to join this big star gazing community! I realize I am abusing of your kindness, so that you in advance for any help you can give.
I have an old telescope, what appears to be a Meade ETX 90 from the early 2000s. I cleaned it pretty well after many Youtube videos and online research. I found full blown spider webs and dead spiders!
I have encountered a few of issues as I'm putting it back together and I wonder if anyone might be able to help.
1. I took off the screws of the back of my OTA (I know I shouldn't have!) and now I'm not sure how to put them back on (see attachments). When I try it seems to push the primary mirror instead of fastening to anything.
2. My secondary mirror flip is broken, the plastic piece part fell off. Is it possible to fix? The mirror itself is also very dirty (see attachments) and I don't think it can be cleaned further. Any tips on how to replace it and where to buy the parts? Or is it possible to not use the 90 eye piece viewport and instead use the front one so I don't need to fix the flip or the mirror?
4. My secondary baffle is sliding off. I've read that this is a problem w/older models. I tried pushing it to the right place and it requires some force, but after 1 minute it slides back to its original place. What should I do? Does this matter?
5. The plastic attachment to hold the smaller lens (finderscope?) wobbles no matter how tightly I screw it on. I don't know if it has anything to do with the front plastic part being a little broken.
Thank you for your help in advance, and I am still learning terminology so be easy on me