spaceman_spiff

I was more worried about the Sahara dust whipped up by the storm covering my optics!

Welcome Victor, I use the same scope for planetary, lunar and solar imaging. It really is a great scope. Dan.

I had been watching the weather forecasts all week and was really looking forward to Saturday night. I set up at about 5pm at about 7pm I had a small opening in the clouds and was able to polar align. After that, it was complete cloud cover. My wife and some friends were watching a film and I chose not to watch it so I could focus on the astronomy (I am kind of antisocial). At 11pm I packed up feeling pretty annoyed. I don't know when the next clear moonless night will be since Ophelia is on its way. I get the feeling that was my last chance this month...sigh.

Welcome Lobo, I also agree with @Adam J . You have started well: you know you want to do AP, you know and appreciate polar alignment (although polar alignment will need to be more accurate with greater focal lengths). Now you need a solid mount. The HEQ5 and EQ6 mounts are the standard astrophotography mounts and have a huge following. I started with an EQ5 and it is a good mount, I could put a 120 f8 refractor on it with a guidescope piggybacked and it did work...just. I did lose quite a lot of frames which prompted me to go for the AZ EQ6 which is far more steady. Your 500mm Canon lens sounds great for AP, it should illuminate your FF sensor and give a FoV that covers big targets like M42, M31, Heart and Soul nebula etc... One issue I've heard of using these type of lenses are diffraction effects caused by the aperture blades, I don't have one so I can't say if this is a common problem from experience. Also, as mentioned getting filters for a big sensor can be difficult. Guiding will be necessary at some point because it combats the effects of sub-perfect polar alignment, mechanical imperfections in the mount, wind and other disturbances that can affect your images. I use a ST80 and a synguider and it works well for me. Others use different set ups, e.g. adapted finder scopes (cheaper than ST 80) fitted with guidecams controlled using a laptop. There are lots of options! HTH! Dan.

I do the altitude adjustment first and then tighten the clamps. I then sort out the azimuth adjustment. The mount holds polar alignment very well for the rest of the night. Dan.

Seconded! This is typically the result I get after stacking movie frames. Wavelets will bring out the sharp features of the image.

Looks like a bright object (Aircraft or maybe Venus) that has been smeared out due to camera shake. The shape looks too irregular to be star trailing. You say you were looking for the meteor shower (the Draconids?) there are no planets in that part of the sky so I'm thinking it's probably a plane. Dan.

Good to know vlsiv. When I get my stacked images, I'll play about rescaling them and see if the fit better. I'm sure the scaling factor could be predicted but I'll do it by trial and error. Something to keep in mind when imaging the moon over the course of a night!

Thanks vlsiv, interesting link, So does changing the focus point in the Mak will then change the image scale? I am not changing the back-focus distance, only the distance between the primary and secondary mirrors.

Stellarium shows the moon's distance (and scale) oscillating each day.

Hmmm, I image using only a very small 640x480 array of pixels in the centre of the sensor. I would have thought barrel/pin cushion distortions would be minimal there.. Thanks, I try to reach focus from the same direction to reduce the mirror shift but it could always be happening anyway.

Thanks for that, Maybe some type of mirror shift is happening, I hope not! I use Gimp to stitch the panels together (using the difference between layers to get a precise match). I'll see what happens tonight.

Morning SGL, I am planning on getting my Mak back under the moonlight tonight to do some imaging (it's been so long!). In previous imaging sessions I would move along the terminator taking ~30 video recordings to stack. More often than not, the stacked images would not perfectly overlay. I made sure I refocused roughly every 90 mins, so it's unlikely to be the telescope's fault. It has just occurred to me that as the Earth rotates I am moved towards the Moon (as it rises) and then away again (as it sets). I now think this is causing a slight change (about 20 arcsec change in Lunar diameter) in my image scale and making my mosaic not fit together. Do you agree? Or it is something else? Dan.

Your welcome!