Stub Mandrel

Altitude, I've seen a difference as big as that between last year and this year!

I missed a clear night yesterday 😞

Spent the evening at a band meeting, then got back to a houseful..

Thanks Folks,

That's useful feedback.

The accidental materialisation of another bass may set this project back a couple of months...

22 hours ago, OJ87 said:

Hi, 

actually I got a lot of troubles running Toupcam too.. 

After a lot of pain I got it work fine in Toupsky , but it makes a lot of problems with PHD 2. It keeps disconnecting from PHD 2. The drivers are there, even after the last PHD 2 version, which supports Toupcam cameras. I tried the development version, it also didn't work. I'm regarding that day, in which I bought this cam.. I hope I could sell it and buy ZWO.

I've got it working OK in Sharpcap.

PHD2 makes it hard to 'fine tune'# et camera, it seems the 'advanced' options will let you set the gain.

OK, while it's a nice thought to blow a grand on a camera, I have better use for such amounts of money 😞

So, are there any views on the ASI174MM out there from people who have used it?

Does it respond well to darks?

Is it feasible/worthwhile to cool it by insulating it and attaching a peltier to the housing (I know this won't be as effective as built in cooling).

Is it a step up compared to a cooled or mono DSLR?

Has anyone got a few example images?

13 hours ago, MarsG76 said:

I too am surprised just show much detail can be squeezed out of a video that at first glance looks like there is nothing useful there....

 

To be fair, that was a clip of one of the worst bits, the best footage that night was of Saturn when the cassini division would occasionally be visible. But compare the best Jupiter from that night with the sort of images I got last year, all with the same 6" scope:

Worrying thought...

If these product soften the epoxy, is it possible that it could peel off and take the gold contact wires with it?

7 hours ago, Swoop1 said:

More Yay!

You must call it Dirk... 🙂

On 18/11/2017 at 04:39, Uranium235 said:

Heh  somehow I don't think you will be ditching that 130 anytime soon, you're getting some good stuff out of it! A victory for the bargain basement of telescopes  

Do you still get all your images with a 1000D and an ASI 178?

Do you use photoshop?

Give gradient exterminator a try:

11 hours ago, vlaiv said:

Don't debayer in PIPP so keep option "protect bayer matrix" turned on.

This is something I learned the hard way, especially if you want to drizzle in AS!3. I now always debayer in AS!3

Looks nice to me. I popped a screen grab through 'gradient exterminator (using a selection excluding the nebulosity and with balance background ticked.)

I then used 'selective colour' to reduce cyan in the red channel - a tip I got from Olly.

More aggressive use of gradient exterminator, than a few runs of 'increase star colour' - some lovely blue stars appeared. Great data 🙂:

On 26/07/2019 at 16:02, Prolifics said:

I put them in deepsky stacker and made a reference frame for each of LRGB images and got them all to stack fine and saved them as L.tiff R.tiff G.tiff and B.tiff. Each colour are aligned fine. (now each colour are all the same way up)

You need to use the same reference frame for all images. It doesn't matter if the reference frame is (e.g.) Red and you are stacking Blue, just uncheck it and check the blue images and tell it to 'stack images'. The unchecked red frame will be used as refernec but not included in teh stack.

This will align them all the same.

To me it looks like it hasn't been debayered.

I aready have ZWO RGB filters and a filter wheel...

5 minutes ago, vlaiv said:

Of course, point of sensitivity of camera is not how bright things look on screen as you can adjust brightness (do different range scaling, or apply non linear histogram transform). Point of sensitivity is achieved SNR in given time with light source of set intensity (and other things being equal - like sampling rate and aperture).

I think my worry has been is that with apparently 'similar' settings - maximum gain (to allow shortest exposure to fight seeing) and the display settings (brightness, gamma all on default) - the mono cam + a colour filter has appeared much less bright for a given exposure than the colour one.

Now I know this isn't actually a problem and I can compensate by turning up the display brightness to compensate (effectively mimicking the extra gain) and rely on a combination of Sharpcap's Histogram 'brain' to ensure I keep the planet part of my data out of the 'red zone' while keeping the exposure as short as possible.

It also give me the confidence to try again on Venus with my extreme UV-pass filter.

9 hours ago, vlaiv said:

I'm not sure how the measurements were made, but e/ADU part needs flat panel to be established. If you did use flat panel, then it should be measured value, if not, it's probably read from driver instead.

Diffuse and rather low daylight.

See if I'm getting this right?

As (in principle) the only difference between the sensors is the bayer filter the QE should be the same and to a first approximation, the mono cam will collect about three times as many photons per pixel per unit time.

Any other differences come from the electronics.

So let's assume that at a particular level of white light you get 100e on the mono cam and 33e on the colour.

At their maximum gains this gives 213 ADU and 305 ADU respectively, so the colour will appear over half a stop  brighter if these are scaled directly to display levels, even though the mono image has three time the 'real' qauntisation depth?

I've managed to get some comparative results for my Touptek Mono:

And ZWO ASI120MC:

These both use the SAME chip, and I would expect the mono version to be more sensitive, but in Sharpcap it appears LESS sensitive.

I THINK these figures explain why - the ZWO has much higher gain giving the apparently 'brighter' image, but at about 0.1 e/ADU this is at the expense of dynamic range and not actually giving me more data.

The mono cam has a sudden drop in read noise  at 200 gain - I assume for long exposures this will be the best setting balancing noise against dynamic range.

Note both cameras were very warm (about 27 degrees) for this test.

Can anyone help me better understand these figures?

Has anyone got a Toupcam to work with Sharpcap and Toupcam drivers?

I can only get mine to work with the 'GPCAMAR0130C' driver and the results are disappointing.

Thanks @vlaiv that's useful food for thought.

ED 66 66mm x 400mm

130PD-S 130mm x 590mm (with coma corrector)

150PL 150mm x 1200mm

Using the f/3.6 rule, I get optimum pixel sizes of  1.68, 1.26 and 2.2um.

If I use a 0.5 focal reducer these pixel sizes halve.

The ASI 183 has  2.4um pixels and the ASI1600, 3.8um, to me the ASI183 seems better match?

I know there are other ways of calculating the optimum pixel size and it depends on seeing & guiding as well. On all but the 150PL my RMS guiding on a good night is <=1 pixel with the ASI183.

With 150PL I'd  experiment with binning in processing.

I am agonising about this.

The ASI 183 is better suited to small DSOs with a pixel scale very well matched to my scopes, and offers potential for binning while still keeping a decent final image size. The smaller sensor means any residual worries about field curvature with my frac evaporate; I could also use my 0.5x reducer to get a wider FOV so it could effectively frame anything the ASI1600 can.

The ASI1600 has a bigger FOV but will undersample and would not suit tiny targets.

But these differences are marginal.

The issue seems to come down to the amp glow of the AS!183 versus the microlens artefacts of the ASI1600.

Any purchase is some way off, but I like to have an 'end in view' and a decent cooled CMOS mono cam is pretty much where my upgrade path can end -aside from finding better skies...

It is an agonising subject to debate.

2 hours ago, wesdon1 said:

Hi, may i ask what magnification you were using when recording that video of Jupiter at top of your post ? Also, what 'scope were you using ? Thanks, Wes. ( Newbie based in Liverpool, UK )

Hi Wes, I image planets with a 150PL an x3 barlow, a filter wheel (left on IR/UV cut for my colour camera)  a ZWO Atmospheric Dispersion Corrector and a ZWO ASI 120MC.

There isn't really a magnification for imaging, it depends on focal length and pixel size, but my equivalent focal length is 3,600mm which is quite long.

I hope to make an equatorial platform in time for mars next year, so i can use my 10" dob which should start to open the door to some good results.

2 hours ago, Aussie Dave said:

You should be able to get similar Neil with more stable seeing near their highest elevation.

I hope so - looking at my results I started when Jupiter was in Orion using webcams. Each year my gera and technique got better but Jupiter got lower and my image quality stayed more or less the same. Hoepfully over eth next six years both my skill and the seeing will improve together!

10 hours ago, Noobulosity said:

I've gotten one response from a chemical company, so far.  They recommended KMG GenSolve 475, which just stated that it's an organic solvent and is about $400 for a gallon bottle.  No actual data on the solvent type used.  So, unless someone knows more about it, that feels like a dead end.

From the MSDS:

" The identities of the materials in this product are withheld as a trade secret (29CFR1910.1210(i)) and are available to a physician or paramedical personnel in a emergency situation."

It's always worth a try googling <product name> MSDS.

bear in mind that the fundamental solvent is only going to be one of a fairly liomited range of options, it's the additives they keep secret.