Pinarello87

Really lots of tech talk here. I know its important to get good alignment etc. 

from where I am imaging on my balcony i dont have Polaris in view and much reference stars to do a really good drift alignment (being at equator 3 degrees north). I have to take exposure subs of the brightest star i can find  between 30secs to 60secs long to see where the drift goes and adjust my azimuth/altitude accordingly (this after proper leveling of mount) until i dont see any drift. Ive managed to push 90'' subs with very minimal drift noticed. 

Thats the drifting alignment i do now. So far it works enough for me and i get a rather decent image of M13 like below (you will still see the walking noise there)

So with whatever i do and learn now until i get better and better I hope to digest the technicalities as I slowly progress on. 

At least i know the root cause of the problem, understanding the solution to it, and then practice it every time I do my imaging. 

21 hours ago, newbie alert said:

If you do a 10 sec delay in the exposures you should get a natural dither, if not then a 20 sec delay..

8 hours ago, michael8554 said:

DC is tracking but not guiding, so no RA dither unless his tracking rate is way out .....

Michael 

So does this mean to manually dither in RA using this 10-20sec delay is pointless? If i dither manually in dec would it be different? 

Im not upgrading to guiding so soon yet. So i guess i need to do more work i guess. 

On 16/05/2019 at 04:36, wimvb said:

This is so called walking noise. It's caused by offsets between exposures. You can get rid of it if you dither between exposures (= move the mount slightly in a random ra/dec direction). For the subs you already have, use more aggressive pixel rejection while stacking.

On 16/05/2019 at 05:47, michael8554 said:

Dither would do, it but I see you aren't guiding, which makes random 10 to 15 pixel moves difficult.

Michael

Thanks guys for the advice. 

Cheers

On 13/05/2019 at 21:56, tooth_dr said:

I've had this happen a few times with my EQ6, to no ill effects.  It's moving at sidereal rate.  I wouldnt fancy doing it when slewing at full speed.

On 14/05/2019 at 04:42, Ibbo! said:

I have do it with my mount a couple of times.

I think the stepper motors effectively stall.

On 16/05/2019 at 15:40, Carbon Brush said:

The great thing about stepper motors is that they do not take excessive current (and burn out) when stalled against a solid object.

With the tiny (low torque) motors used in scope mounts, there should not be an issue running slowly against a hard stop.
The Skywatcher design team should have thought about this situation and ensured the gearbox is up to handling stall torque.
On a mass produced item there is no excuse for basic design errors.
Speaking here as someone who has used stepper motors with 100x the power of mount motors on industrial machinery.

Caveat - Some mounts do have tiny parts around the gearbox and bending is possible.
The (expensive) AWR drive on my D6 drive suffered a bent shaft in the gearbox after mount impact.
 

 

Cheers guys

Thanks for all your input

Hi forum. 

Need some advice from the seniors and pros. I just started AP for 2 months and am enjoying the process. 

I use a Skyrover 60ED apo with FF and a optolong moon filter. Use an unguided EQ3 goto mount. Dslr is a nikon d3100. 

I was imaging Centaurus A with about iso 400, 30x 45" subs. Flats biased and darks use in my image stacking with DSS. I use Gimp to do final editing. 

I observed lots of uni directional lines if i pull up the levels high enough. Its all across my image. Im wondering is this some kind of fault within my image train or my dslr sensor? 

P/s i was cleaning the filter and flattener so i wonder is this a smudge also? 

Any ideas or experiences to ecplain? Below is a pic sample of part of the image. 

Thanks much. DC

Very well done. Perfect id say. Give hubble a run for its money 

My first DSO was also M13

This was about a month ago. 

SkyRover 60ED f6 Apo + field flattener + Optolong moon filter. EQ3 goto mount. Nikon D7000 unmod. ~20 x 30" ISO400. 

Tracking, non guiding

Used DSS and Gimp to make the final image. 

Hello SGL. Im new in here. 

I just entered AP 2 months ago. Its been a great time so far. So i hope to learn more from this forum. 

I have a 60mm ED Apo on a SW EQ3 goto. 

Anyway as the title suggest, i was doing a really late long night imaging from my balcony last night. I was imaging Centaurus A with my rig set for 70 x 90" subs. While waiting i kind of dozed off till several hours later. 

Seeing the mount had reached its maximum RA tilt and i assume its been that for a good 2 or 3 hours with the scope right against the mount head. I quickly turned everything off. Slighlty worried. 

Will this cause any damage to the RA motor? It wasnt burning hot. Just warm. I have yet to inspect and test the motor. 

Advice please fellow senior forumers and AP gurus. 

Thanks a bunch.