The "No EQ" DSO Challenge!

[Filroden]

4 hours ago, The Admiral said:

Can StarSense and ASPA be used together, or do you have to align conventionally before using ASPA, and then switch to StarSense? ASPA does appear to take a lot of the pain of polar alignment away, and works when you don't have sight of Polaris, but I wonder how good an alignment you can achieve, and the maximum length of sub you can use. I guess it also requires precise centring of stars, so does that mean using a graticule eyepiece rather than centring on the live view image?

Ian

Based on what I've read in both the mount and StarSense manuals, I think my process will be:

1. Level mount and roughly align it to pole using alt dial and eyeballing direction of mount using a compass (eventually putting down marks on the ground to make this step quicker)

2. Achieve focus on bright star

3. Run StarSense (auto or manual) alignment routine to generate a sky model (this would have been a two star alignment routine using the original handset)

4. Ideally add additional alignment points to improve model

5. Run StarSense polar alignment routine which will slew to a bright star near meridian and ecliptic (this is similar to how the ASPA routine would also work using the original handset)

6. Adjust alt and az mount controls to centre star (using 'live' view on laptop which is graduated and can be enlarged for precise alignment)

7. Re-run StarStense (auto or manual) alignment routine to re-generate a sky model (which will have changed depending on how much adjustment was needed in previous step)

8. Begin imaging

9. (in reality, go back to step x and repeat until right)

So in practice this will take longer than my current set up as I have to do the alt/az adjustments and re-run the StarSense in addition to the normal StarSense alignment I do now. However, a manual StarSense alignment takes a few minutes at most and I'm hoping the polar alignment step should only be a few minutes too as it's very similar in process to adding a calibration star (just using the manual alt/az knobs to centre the star rather than the arrow buttons on the handset).

I think this process can result in getting to within 0.5" of the pole and should be good for 60-120s exposures. Guiding could then allow longer exposures. I need to read about drift aligning which I think is a technique for further improving the alignment but given I don't want to use very long exposures, I'm hoping to avoid this.

[The Admiral]

Thanks Ken. So, if it works , that's quite a slick routine. I wasn't aware the StarSense could do that, and the device certainly helps automate the operation.

By the way, I see that FLO are now offering the EVO mount, on its own, for ~£900, so Alt-Az imaging isn't the cheaper entry option as it was with the Nexstar SE (it cost me about half that), and is on a parr with EQ mounts. True, there is the Star Discovery but its load capability is lacking.

Ian

[Filroden]

57 minutes ago, The Admiral said:

By the way, I see that FLO are now offering the EVO mount, on its own, for ~£900, so Alt-Az imaging isn't the cheaper entry option as it was with the Nexstar SE (it cost me about half that), and is on a parr with EQ mounts. True, there is the Star Discovery but its load capability is lacking.

It's my mount but I have the better tripod (the 9.25" comes with a heavier tripod). Given how well I've found that it tracks (rotation aside) and it has battery and wifi integrated, I think it's comparable in quality to some of the similar priced EQ mounts. I'd rate it very highly as a good alt/az mount but I have nothing to compare it to. I'd still like to see reports of the hybrid AltAz/EQ mounts and how they perform in both modes.

[SteveNickolls]

Hi Ken,

Without going back deep into the thread can you tell me how long you were able to sustain tracking with the EVO mount on your imaging sessions? 

Cheers,
Steve

[Filroden]

Just now, SteveNickolls said:

Hi Ken,

Without going back deep into the thread can you tell me how long you were able to sustain tracking with the EVO mount on your imaging sessions? 

Cheers,
Steve

Once aligned, it would hold position for the full session though that would only be a couple of hours for me (I'm a lightweight). Originally I would reslew to the target every 30 minutes or so as it randomly (it seemed) would occasionally slow its rate of tracking and the target would start to drift slowly. I swapped from battery to mains and this seemed to cure the worst of it so I think it was probably just me letting the battery run down too much over multiple sessions (rather than recharging before each session). I think some of it is also that my scope is now very imbalanced on the mount with all the imaging equipment, so I'm putting a lot of stress on the motors, which could be affecting their track rate. I really should have got an extended bar to move the scope further forward or add weight to the front. I'm hoping this won't be an issue with the new mount as it has to be (almost) balanced to be effective.

If it was going to be 'funny' about tracking (e.g. fail to track in alt or az) it would do so quite quickly and noticeably. A quick cycle of the power switch sorted it (though it did mean doing a realignment). Once rebooted it would again hold position all night.

Of course, this is only my anecdotal evidence. I haven't plate solved my images over a session to see if the centre point remains constant. It certainly felt constant enough for me not to care! I'm working away from home until next week but when I get back I'll take a look at a lengthy sequence and plate solve the start, a few in the middle and the end images to see how it went.

[SteveNickolls]

Thanks so much for your account of the mount's tracking over an imaging period Ken, it's such a difficult point to establish without user feedback and the little foibles that can creep in now and again. I'm interested in what you've said about the battery performance issue you experienced as being battery powered was a plus point for the mount, adding to its potential for portability. I'm pleased you think a recharge between sessions would be ok for it, that's good news. I've got similar issues with balancing with the SkyWatcher Synscan alt-az mount and my telescope set up is quite back heavy but as this season I've been mostly imaging with just with a camera and lens (no telescope) that has not been an issue to resolve immediately. I ought to get a longer dovetail for when I do go back to using the telescope. Can I ask what exposure lengths you have managed to get with your Evo set up Ken? I find my SkyWatcher Synscan is ok to around 60 seconds for favorably positioned objects and returns very high percentages of frames acceptable to use in DSS. At 70 seconds the mount's design starts to let it down and the percentage of stackable frames plummets.

Cheers,
Steve

[Filroden]

4 hours ago, SteveNickolls said:

Can I ask what exposure lengths you have managed to get with your Evo set up Ken?

I never have any trouble with 60 second images other than if pointing too close to the meridian. I've not experimented too much with longer but it seemed ok at 90 seconds too if pointing to the east and I did do the occasional 120s just for fun (all at a 400mm focal length). However, I found 60s was more than enough to swamp read noise so there was no incentive for me to push it further.

I think it's a solid mount. I think it does need to be reasonably balanced to avoid stressing the motors (probably another contributory factor in battery being run down over a number of sessions). It certainly feels solid and I never felt worried when I had the SCT on it (which balanced very easily, even with the camera attached as its bar was much longer). The only annoyance was how it whined as it slewed at its top speed. I was always concerned it would wake the neighbours. I don't think it actually was that loud but when you are outside at night even the slightest noise feels loud. 

[SteveNickolls]

5 minutes ago, Filroden said:

The only annoyance was how it whined as it slewed at its top speed. I was always concerned it would wake the neighbours.

Thanks for confirming the capability of the mount Ken for alt-az work. I know what you mean about loud slewing and being outside at night time. 

Good luck with the AVX by the way.

Cheers,
Steve

[The Admiral]

On 24/02/2017 at 10:45, Filroden said:

I think this process can result in getting to within 0.5" of the pole and should be good for 60-120s exposures. Guiding could then allow longer exposures. I need to read about drift aligning which I think is a technique for further improving the alignment but given I don't want to use very long exposures, I'm hoping to avoid this.

Ken, I'd be very interested to hear just how good the alignment is just by doing the 'soft' alignment using the StarSense, and what sort of exposure durations you in fact do achieve. If they are good without too much trouble the prospect of EQ imaging for me is more attractive. The reasons I never went the EQ route was because I don't have sight of Polaris and as I set up from scratch each time I image I really don't want too much hassle - life's too short as it is! Guiding and drift aligning really is a step too far.

Not that the weather is co-operating!

Ian

Edited February 27, 2017 by The Admiral

[Filroden]

I'm expecting delivery on Thursday so I'll experiment with exposures with just a StarSense assisted alignment. 

[Filroden]

On 2/27/2017 at 11:59, The Admiral said:

I'd be very interested to hear just how good the alignment is just by doing the 'soft' alignment using the StarSense, and what sort of exposure durations you in fact do achieve.

Rather than add any further EQ contamination to the thread, I've created a blog of my experience (so far) with the move to EQ.

 

[ManixZero]

Starry nights have been few and far between but I have had the chance to point my Nexstar 4SE+Pentax K5 combo once more at M42.

I'm still struggling with focusing and blurring, but I'm sure I'll get there!

 

I have now added a 32mm eyepiece to my arsenal which, I hope, will help me find other objects of interest! 

Cheers

MZ

 

[happy-kat]

Clear night you lucky person :-) How many lights was that and of how long?

Orion is very much in the South now less ideally placed for AltAz imagiing.

To find objects of interest is your GoTo not working? Though the 32mm will be a nice additon to your 4SE.

 

[ManixZero]

1 minute ago, happy-kat said:

Clear night you lucky person :-) How many lights was that and of how long?

Orion is very much in the South now less ideally placed for AltAz imagiing.

To find objects of interest is your GoTo not working? Though the 32mm will be a nice additon to your 4SE.

 

Single image...still haven't got the hang of stacking yet.. 30 seconds 1600 ISO.

As for other objects.... The goto works fine - it finds M42 - however when I choose anything else there isn't anything to focus on in either the eyepiece camera! 

I will get there, I'm sure, just brand new to this so don't really know what I'm looking for or at or even what I'm doing!

 

Cheers

MZ

P.S.  I found a Planet!

[happy-kat]

Use Stellarium to think about which target then find the nearest bright star to it and slew to that, focus on that star then slew to your object of interest.

[ManixZero]

19 minutes ago, happy-kat said:

Use Stellarium to think about which target then find the nearest bright star to it and slew to that, focus on that star then slew to your object of interest.

This is something that I will definitely try!

 

Thanks

MZ 

[Nigel G]

On Friday, March 10, 2017 at 23:11, ManixZero said:

This is something that I will definitely try!

 

Thanks

MZ 

Good efforts, keep at, the stacking bit will come.

Try taking about 40 x 20s at ISO 1600 on M42 to start. Take these in raw files. Then download Deep sky stacker ready for the next step.

Load the light frames into DSS and stack. The final stack will then need processing as it will look very dark and featureless. 

Adding bias and flat frames will be a step in the right direction but for now just try light frames.

Offset frames are easy to take and make a big difference to the processing. 

Nige.

 

[The Admiral]

On 10/03/2017 at 21:42, ManixZero said:

Starry nights have been few and far between but I have had the chance to point my Nexstar 4SE+Pentax K5 combo once more at M42.

I'm still struggling with focusing and blurring, but I'm sure I'll get there!

Cheers

MZ

Well, you have to start somewhere! And that's a good start. More often than not it all comes down to total exposure, so you'll have to get into stacking, and teasing out the detail with processing. That can make or break an image. But don't give up .

Ian

[The Admiral]

With this lousy weather we've been having I've not been on here much, but with our first clear(ish) night for ages, and despite a 90% Moon trying to get in on the act, I had a go at the Leo Triplet. When I brought the gear in it was dripping, so I think that there was a lot of water in the air, though I think the seeing was reasonable.

Better than I thought it would turn out, considering, but when I look back at what I'd achieved a year ago I think this is certainly no better, despite double the number of subs. Rather noisy. Previously I'd not used the 0.69x reducer/flattener, which may have given me larger view in the frame, but I thought that the more 'concentrated' photons would yield better results. May be I'll try again if better conditions present themselves, because I really wanted to improve on my earlier exploits. Perhaps with such small objects I've reached the kit's limitations.

This image is comprised of 180 x 30s stacked subs, taken 16 March 2017. Subs were stacked with AstroArt, processed in StarTools, using the colour module and final tweaking in Lightroom. No darks, just flats and a master bias. Equipment:  Fuji X-T1 through an Altair 102mm f/7 Super ED with a TS Photoline 2" 0.79x reducer/flattener. Mounted on a Nexstar 6/8SE Alt-Az mount.

Ian

[Filroden]

1 hour ago, The Admiral said:

This image is comprised of 180 x 30s stacked subs, taken 16 March 2017. Subs were stacked with AstroArt, processed in StarTools, using the colour module and final tweaking in Lightroom. No darks, just flats and a master bias. Equipment:  Fuji X-T1 through an Altair 102mm f/7 Super ED with a TS Photoline 2" 0.79x reducer/flattener. Mounted on a Nexstar 6/8SE Alt-Az mount.

You picked a tough time to image. The moon will have given you a bright background, and a corresponding amount of noise to go with it. When you removed the gradient it will have left a lot of noise from that background. I don't think any amount of subs will help you overcome an almost full moon

I also found imaging such (relatively) small targets with only 80mm of aperture quite disappointing. I think you got more detail than I achieved though you have an extra 22mm of aperture, so that's to be expected. Unfortunately, we're heading into galaxy and globular season, with Cygnus not swinging far enough around until the early hours. 

[happy-kat]

Had hoped to have got the comet 41p this evening but alas it was too high and the gutter was in the way. My 8 inch lens shield is not long enough if I am N-SE the super bright 15 feet away street light (not the one in the photo several pages back this one is worse it is like right over my head!) was managing to shine right down on the lens. The mount tracks much better (for the camera) if the object of interest is in the region of the second star used in alignment. I was able to get 30 seconds and reasonable stars at 80 degrees elevation didn't take many shots as I was having to hold my seat cushion up by hand to give an extra foot of protection from the street light. Just took the Owl as it was where I had aligned for the comet just for fun as what I had hoped to do I couldn't I will have to wait for the comet to get higher and over so I can sit out back to do it if it doesn't fade away before then. Lovely dry evening no moisture in the air but it was a bit windy. Still on the original charge on the battery think this is 7 uses now.

[happy-kat]

Crop of something and I should have used ISO 1600 I think. Fuzzy patch is either comet or owl neb I need to compre to skysafari screen grab of location taken last night. There are two fuzzy bits I thinking the larger slightly green one. Lens has CA when wide open it is not worth stopping down as it is there too about f8.

Edited March 22, 2017 by happy-kat

[SteveNickolls]

You are in the right location happy-kat, the green object is M97 I would say going by the nearby stars patterns and the spindle shaped object is a likely M108 (Surfboard galaxy). Stellarium shows Tuttle to be nearby but perhaps just out of frame. Don't know the time of your imaging. Well done anyway. Can I ask the details of the imaging?

Cheers,
Steve

[Filroden]

I'd agree. You've definitely got the Owl and M108 in frame.

[happy-kat]

Thanks Steve and Ken. It's a crop so I might have it anyway. About 9-10 pm. Iso 800 30s 135m! Lens. I aligned on m108. Elevation 83°

I've got 22 lights but stacking will be tonight.

Edit: I've got the comet yey though don't think it will process great it's a fuzzy faint one unlike lovejoy was.

Edited March 22, 2017 by happy-kat