The EQ3 DSO Challenge

[bobro]

1 hour ago, wimvb said:

I would advise to first take care of backlash in ra and dec, before stripping the mount.

Hi Wim,

As the setup in question isn't guiding but just tracking in RA (hence DEC not driven and RA always driven in one direction), could you explain why reducing backlash in RA and DEC would help?

Thanks

[wimvb]

You're right, as long as you don't guide, DEC backlash is of less importance. But it will affect GOTO accuracy as well. That's why you always have to end a GOTO alignment with RA+ and/or DEC+ movement. You just need to approach an alignment star from the same side. Otherwise any backlash will throw the alignment off.

If you use guiding, a polar misalignment will help, as recently explained by Olly. (You only need to correct DEC drift in one direction)

[bobro]

Thanks Wim, though you could be corrrect in that checking the tightness of the worm gears would be worthwhile in case binding is taking place. Much quicker than a stripdown!

[Art Gecko]

welcome @jjosefsen to the EQ3 challenge! All the advice you received above is good sound advice and I stand by what these good people have said.... But before you go stripping your mount I'd like to say that 40% retention is not actually all that bad for unguided imaging... If you take a look at my M31 you'll see I was down to 27% on that image!!

I would say definitely check/adjust your RA axis wormgear a little and see if that makes a difference, and as Neil said, try biasing your balance to the east.... New grease will make an improvement especially for those who are autoguiding, but if you're not autoguiding, you'll only be using one motor for 99% of the imaging session, your dec axis will be locked in place so there's really nothing you can do about periodic errors other than get your polar alignment as spot on as possible.... If you decide to go for autoguiding, then it'd be advisable to do the strip down and regrease as both motors will be under a heavier work load and the upgraded lubrication will be essential... But until then I'd save yourself the effort and give yourself a pat on the back for what you've managed to acheive so far!

Oh yeah, and wind factor does make a big difference!! Remember you've only got to move your scope a couple of millimetres and the field of view will change by several degrees... you may not be able to see the scope moving in a light breeze, but it will be evident when checking your subs.

HTH Art.

Edited August 3, 2017 by Art Gecko

[Nigel G]

If your not happy stripping the mount down yourself, there are companys who service mounts like astrotec at a cost of about £100 + postage.

Nige.

[Stub Mandrel]

FWIW I go through my subs, take out any ones with clearly bad stars, then stack 80-90%.

If you use DSS with sigma-kappa stacking it does a good job of rounding up you stars as long as the errors aren't all in the same direction (i.e. caused by wind or vibration, rather than a consistent blurring caused by bad PA.)

[jjosefsen]

Thanks again guys, good information here as always.

 

[mikey2000]

Some more from me...  I've finally had time to process these.  The night was clear to start but soon covered over.  Hence the short exposures on these ones.  I hope to revisit these for more data

 

M27 Dumbbell Nebula  (6x12 mins)  The clouds were drifting slowly in so I gave up on this one and shifted to the Iris nebula.

 

NGC7023 Iris Nebula.  (7x12 mins only and the last two were distinctly hazy, just before total cloud cover...)

[Stub Mandrel]

I love the Iris Neb one!

[wimvb]

Me too! My first impression was that you'd clipped the background. But zooming in reveals faint variations.

If you can find the time (and the hole in the clouds), more data can reveal the subtle difference between the dust clouds and the true background. It's easier to get to this level of detail if you have really dark skies.

Thanks for sharing.

[mikey2000]

:-)  Hoping for some clear skies tomorrow or saturday....  That Iris nebula is in just the right spot at the moment - it's in my darkest patch of sky (quite high and on the other side of the garden from the Milton Keynes LP...)

[Stub Mandrel]

9 hours ago, mikey2000 said:

:-)  Hoping for some clear skies tomorrow or saturday....  That Iris nebula is in just the right spot at the moment - it's in my darkest patch of sky (quite high and on the other side of the garden from the Milton Keynes LP...)

That bit of sky, high up in NW is good for me too, but rarely seems to have anything in it! It would make an ideal target to try out the C90.

[Nigel G]

StarTool users, have you ever done this. I have several times  

I just spent 1.5 hours processing the Crescent neb 6 minute subs only. Looking real good.

Next to the + zoom tap is the x close program tab, I'm sure you can guess what happened  

Nige.

[alacant]

24 minutes ago, Nigel G said:

have you ever done this

Yes. There's a discussion on the st forum. Ivo doesn't want to second guess with an are you sure, so we must be careful. I think it's something you only do once though!

[mikey2000]

Yes!  I wish there was a "save recipe" option in StarTools...   

Mine sometimes just crashes unexpectedly, the effect it's the seams.

now, there is a log file somewhere in the StarTools folder.  It keeps a log of every processing step you ever did so you can at least manually rebuild the same steps you previously followed.

 

I'm away from the computer so I cant give the exact location though

[happy-kat]

There is a log file is in the startools folder. 

[Nigel G]

23 minutes ago, mikey2000 said:

Yes!  I wish there was a "save recipe" option in StarTools...   

Mine sometimes just crashes unexpectedly, the effect it's the seams.

now, there is a log file somewhere in the StarTools folder.  It keeps a log of every processing step you ever did so you can at least manually rebuild the same steps you previously followed.

 

I'm away from the computer so I cant give the exact location though

Thanks mikey, I know about the log file  in ST program folder. It's just the time spent  

24 minutes ago, alacant said:

I think it's something you only do once though!

 in my haste I have done it about 4 or 5 times :/

 

Anyway as I promised I have processed the 6 minutes only. My opinion the best being all subs 4+6+10, second best 6+4 minutes, third 6 minutes only. The easiest was all.

What do you think ? I have placed them in the above order. When I look at them all together I can't make up my mind. Theres a bit of a contrast difference there.

Nige.

Edited August 4, 2017 by Nigel G

[bobro]

Although the 6 min version has a slightly different resolution, I find it to have the smoothest colour transitions . Not a lot in it though! How many subs in this version Nige?

Bob

[Art Gecko]

All 3 are excellent, particularly when viewed full size! But for me, the one with 4+6+10 is still the winner

[Nigel G]

2 hours ago, bobro said:

 How many subs in this version Nige?

There is 13x6 minutes, 2x10 minutes and I think around 25x4 minute subs in all.

13x6  

[Allinthehead]

Just remembered this thread. There're some great images taken with this humble mount. My first image on my Eq-3 for at least year. Dusted it down in anticipation of a 2 week trip to a dark sky reserve.

This is 2 hours in 30 second subs 

Sony A7s, Wo Star 71.

Richard.

 

 

Edited August 4, 2017 by Allinthehead

[Peco4321]

28 minutes ago, Allinthehead said:

Just remembered this thread. There're some great images taken with this humble mount. My first image on my Eq-3 for at least year. Dusted it down in anticipation of a 2 week trip to a dark sky reserve.

This is 2 hours in 30 second subs 

Sony A7s, Wo Star 71.

Richard.

 

 

That's a mighty fine Andromeda, I'm currently snapping 30s subs on this now. Moon is washing out the sky a bit though. 

[Allinthehead]

20 minutes ago, Peco4321 said:

That's a mighty fine Andromeda, I'm currently snapping 30s subs on this now. Moon is washing out the sky a bit though

Thanks. Your lucky with your clear sky

[Peco4321]

56 minutes ago, Allinthehead said:

Thanks. Your lucky with your clear sky

Really clear, typical that it's so clear, on a weekend, but the moon is out. Hey ho, just laying back on a comfy chair, listening to the camera snap away (upped it to 45s as alignment was good) familiarising with the star hopping to my upcoming targets with my bins, Bodes Nebulae and double Cluster so I can compare to last years efforts.   Not tonight, but soon hopefully. 

[mikey2000]

Nicely done!   Andromeda definitely looks better in a wider view such as this.

 

it seems you are untroubled by the Sony Star Eating issue...