CraigT82

And a lot more money!

Haven’t done myself but I think that should be fine. Why would a FW allow the use of smaller filters? I would have though the filters would be further from the sensor if placed in a wheel? (Assuming you normally put a filter on the nose of the cam)

Hi Ross, I know your predicament from your other thread about the ADC, I think something you could do is to sell the 2x barlow you’ve got now and get another one with a screw off lens cell, then you could screw it onto the nosepiece of the ADC and you can gain a lot of inwards focuser travel that way. For example, the Baader Q 2.25x barlow is 2.25x natively and has a stated focal length of 44.5mm. The distance from the nose of the ADC to the top is about 84mm so putting the barlow cell on the nose should give you a barlow power of (44.5+84)/44.5 = 2.9x (roughly, this assumes your sensor will be level with the top of the ADC). Just avoid Televue Barlows for this as although their lens cells screw off they do not have a standard m28 filter thread and so they won’t screw into anything else apart from their barlow body.

Forget everything you know about crop factor… it’s irrelevant in astrophotography! What is important is imaging scale - in AP this is what is generally meant by the term ‘resolution’ - it is how much sky is covered by each pixel and the units are arc seconds per pixel (“pp) The guiding performance required is dependent on the imaging scale, which itself is dictated by imaging focal length and the pixel size of the imaging sensor. Ideally you want to be able to guide with an RMS error in pixels of half your imaging scale. So if your imaging scale is 2.5”pp the you should aim to guide at 1.25” RMS With your A7iii and a 360mm FL scope your imaging scale is 3.39”pp which is quite a low resolution. With the same scope and the 533 sensor it would be 2.15”pp. So the 533 would actually create higher resolution images with more detail. The trade off is a smaller field of view. Still the 533 is 9mp and will blow up for printing nicely as long as you don’t go crazy large. Your guiding would need to be a bit better with the 533 than with the A7iii (you’d need 1.07” rms Vs 1.7”rms) so you can check what your existing guiding figures are like to see if your mount can manage it.

It doesn’t shift the focal point so you will need the ADC’s body length of infocus travel (37mm I think) to be able to use it. I’m surprised you each focus with the barlow so far in as normally the barlow will shift the focal point outwards. On my newts I couldn’t use the ADC without the barlow but I could use it with a barlow as it shifted the focal point out far enough. As for the extra barlow power you get for putting the ADC in between the barlow and camera, you can work out what this will be using this formula: Barlow Power = (Barlow FL + Distance) / Barlow FL With distance being the space between the last lens surface of the barlow and the camera sensor.

Really nice shots, nice clear view of the big rift in the NEB.

Nostalgia ain’t what it used to be.

Really nice results, Mars is small but perfectly formed with plenty of detail, will be great to image later at opposition. Nice work with Uranus too, not easy with 8”.

Here is a good one from our very own @MarkRadice

Yeah without a doubt a bigger beefier dovetail is needed with wide ring spacings or with big tubes, I’ve only ever used losmandy style plates with my Fullerscope or my 300p.

As a user of large newts I often wonder about this. I imagine holding a long stick in my hands, holding with hands wide apart would allow you to resist externally applied forces (e.g. like wind gusts on the OTA etc.) better than holding with narrow spaced hands, hence I’ve always gone with widely spaced rings. Also I think as the weight of a newt is concentrated at the ends then wider spaced rings would resist flex in the tube itself better too. Saying that I’m not an engineer and am just guessing really. I’ve seen a few pics online of large/long scopes with closely spaced rings and I’m sure I’ve read something somewhere saying that closer spaced rings were better but can’t find it again. I wonder if there are any mechanical engineers on here who could share their thoughts? Following with interest!

I also use a neutral density filter on my 12” as the image of Jupiter is very bright even at high magnification. Unfiltered it kind of looks like an overexposed image and hard to make out any detail The ND filter is a bit like wearing sunglasses on a bright day and looking wispy clouds on the sky, it takes the edge off the brightness and allows you to see more detail in the wisps (if you get what I mean - not explaining very well)

I’d much rather have the heritage 150 under a good dark sky than the 200p dob under a light polluted sky. I say get the heritage. For what it’s worth I have the 130 heritage ad I love it.

That’s a good point… you could just run off one long 30 min capture and chop it up as necessary in PIPP

Looking at his 3 min test between AS2 only and winjup derotation I must admit I can’t really see any difference between the two blinked images, not on my phone anyway. The 4 minute test at the bottom of the page has obvious differences though. You don’t really see any of the specialist planetary guys running 3 min captures but, remember the OP asked about a 6 inch scope and I think 2-3 minutes will be fine for that (in my opinion).

Maybe half a pixel if captured with perfect optics, perfect collimation, perfect focus and perfect seeing, but in real conditions I disagree. I agree that it’s down to the observer and what amount of rotation they’re willing to accept though, and of course the sampling resolution. I personally use 60 second captures with my 12” newt and they work out well. I think next time I’m out I might do some testing along the lines of that Christopher Pellier did in Neil’s link and see what happens. If anything I think AS3 is even better than AS2 at dealing with rotation, both field and planetary.

On my old 200p the first time I took the mirror cell out I had to use a large flat bladed screwdriver as a drift and tap it out with a mallet as it was really stuck in there. There was just enough of a lip where the cell meets the tube to get the screwdriver onto. After that first time it got easier.

Stopped using Registax a couple of years ago and switched to Astrosurface. It does everything Registax does and a lot more besides, including deconvolution.

The maths for this one isn’t difficult, as long as you know a few key parameters. Jupiter is about 450,000km around its circumference and rotates once every 10 hours ish. So a spot on its equator moves at about 12.5km per second. At a distance of 600,000,000km, 12.5km per second gives an angular distance travelled of 0.0043” per second. With a 150mm scope you’ll be sampling at 0.25”pp let’s say. So it would take 58 seconds for a spot on the planets equator to move from one pixel to the next, but to actually be visible in the image as blur it’d probably need to move at least 3 pixels, so there you have it…. 3 minutes!

Same here on a trip to Tasmania. Upside down Orion and also the moon really is weird to look at.

Well I wouldn’t say it’s common sense but I get your meaning 😂 There is some more in depth explanations further into that paper in section 7 but it’s all Greek to me. Maybe the inventor of the process has embellished it’s capabilities slightly in that paper, wouldn’t be the first time that’s happened!

Looking at the first document linked to in that APP thread it says this about Drizzle and it’s influence on noise, which seems to contradict that quote from the handbook? I’m probably misunderstanding, I admit I haven’t read the entirety of either document.

Really nice result 👍🏼 Amazing what can be done with a manual dob

Yeah could be possible in AS3, using the surface mode and with strategically placed alignment points