Wow, has it been two months since the last post? Well, we’ve both been rather busy of late.
I’ve done a heap of learning since April, particularly how to polar align the NEQ-6 mount and just getting used to working with the new Takahashi E-130D scope and equipment in the dark.
As it’s winter here, quite a few of my sessions have involved a hurried setup, taking a COUPLE of quick shots, then hurrying back in as the clouds cover every inch of sky that I aim at. Quite literally, wherever I see a clear bit of sky, the clouds follow me there, Arrrgh! At least I can say that I’m getting good setup practice.
Was a total mystery to me 2 months ago. Now that I’m more aware of it, I’m getting 3 minute unguided exposures, with only slightly eggy stars. I’m waiting for a new ZWO ASI120MM planetary/guidecam to arrive, that should beef things up considerably.
My now tried and true process for polar alignment involves:
- Bringing out the tripod and standing with its rear leg exactly between my own legs, orienting the tripod towards due south (not magnetic..), using a good old fashioned hiking compass (I tried to use the phone compass but it’s far too sensitive to the metal of the tripod, becoming easily confused).
- To aid this process I have now inserted golf tees in the ground where I can just place the legs next time. But I have to admit, the ‘leg between the leg’ method has proven to be amazingly accurate and quick!
- I’ve also bought 3 small pavers to insert into the ground, to stabilise things even more. Give me 8 mths to get around to doing that!
- I downloaded an excellent phone app, called ‘inclinometer’, in conjunction with my relatively flat sided phone it’s proven an excellent levelling tool.
- I use the app to level the legs of the tripod base until it’s showing zero variation. I then place the heavy scope mount onto the tripod.
- After every session, I remove the head by unscrewing the azimuth knobs 3 turns each, so that I can then place the head next time and screw them in again 3 times, keeping things remotely accurate.
- Of course, before placing the scope onto the head, I screw in the essential supporting rod underneath the mount. I would never forget to do that, would I????!!!
- Balancing weights on, took awhile to work out, but as my scope is fairly light (actually it’s pretty dense to me), both weights are as high as they can go.
- Scope on, triple checking all fixings before releasing the locks for a quick test.
- put the finderscope on and don’t forget to take that pesky aperture cover off!
- Straighten up everything. Put in a nice wide eyepiece, I’m using a 24mm Panoptic, a wonderful wide field EP.
- Enter the time and date in the controller, then do a 2-3 star alignment. I’m still finding alignment a pain, as so many of the stars mentioned are not recognised by ignorant old me! Oh well, it’s a good way to learn I suppose.
- I follow the suggested rule to always slew at the end using the up/right keys, to avoid any backlash issues.
- Now the best bit – I use the excellent polar alignment routine in the controller to fine tune the RA alignment. It’s proven to be amazing. You just nominate a star to align to, make sure the star is centred, then it whirs away from the star a certain distance based on the polar alignment error it has detected. You then correct for the error by twiddling the RA knobs. Voila. I know it’s not perfect, but the fact that I can now get passable 3 minute unguided shots tells me that I’m within tolerance for a guider later on.
- I haven’t had to adjust for the Altitude error, as the scope tells me there is none. I adjust the altitude precisely with the inclinometer app, by placing my phone side onto the scope tube, then adjust. Very simple.
- The Synscan controller can be buggy. The other night I did the alignment and polar routines and it came up with a ridiculously wrong/wide adjustment suggestion. I knew it must have been wrong. A mere reboot of the system and second attempt produced perfect results. The image up top, of the Lambda Centauri neb, was with 20 by 3 minute subs, unguided.
Wonders of Pixinsight
I’d spent a fair bit of money on such programs as Nebulosity and various Photoshop Elements addons, but kept seeing references to Pixinsight (PI).
PI offer a fantastic 45 day trial period for the full version of their software. Such a good strategy that, it sucks you in, gets you used to the great features, then you end up wanting to buy the damn thing! Which is what I did, for a not-insubstantial sum of $190 Euro-pesos. Well worth it IMHO.
Yes the initial interface looks a little confusing. But there are some amazing instructional videos out there, especially by a one Harry Page. Thanks Harry, you sold me on PI, and made it so accessible!
Now I find PI so intuitive, so easy, I’m able to rapidly edit my pics to a reasonable standard in a scarily quick manner. The features that sold me to the program are:
- Amazing, powerful background neutralisation tool, that removes any shading or unsightly patterns caused by light pollution or sensor imperfections. Worth the price of admission alone!
- A green-cast removal tool that is very effective and dead easy to use
- Incredibly flexible and effective histogram adjustments, with detailed previews
- Fantastic noise removal
- very powerful star masks and editing features, making the star masks infinitely controllable
- Some nifty looking HDR tools that I’m yet to fathom
- An effective ‘morphological transformation’ tool that reduces the interference of many small stars when on top of nebulae, a new discovery I’ve just made.
- Pretty effective unsharpening mask, useful in conjunction with the noise reduction
Let’s just say I have little use for Photoshop anymore. Well, not exactly, I can still use it for finely controlled contrast and HDR tweaks. But that’s pretty much my total workflow now. For all the images on this page, I applied:
- background neutralisation
- green cast removal
- noise removal
- star size reduction
- unsharpening mask
- finally, histogram adjustment to stretch the most out of the images.
Enough for now, below are 2 other pics I took on the same rare cloudless night down in Melbourne. Both taken with a new Hutec LP filter, in-camera (in my Canon EOS 40D). Both 20 by 2 mins. The filter must be very good, as I’m able to take exposures of over 5 mins at ISO 800.
My next update should report on the success or otherwise of guided exposures of over 5 mins, and might possibly include some more details on my use of Pixinsight. Seeya in the clear skies!
Jewel Box Cluster:
An earlier Omega Centauri, only 30 by 15 sec exposures due to cloud interference, but I’ll always remember this shot as my first rough decent shot with the Tak e-130d! This is an example of the power of PI’s starmasks, I was able to protect the entire image except for the stars, but also tell it to protect the inner glob. I then upped the saturation to emphasise some of the star colours, but not turn O Cent into a gawdy orange or purple mess: