CraigT82

The lens isn’t removable on that camera. You need a camera where you can remove the lens completely (like a DSLR) and when you attach it to the telescope, the telescope becomes the ‘lens’

1 hour ago, wuthton said:

Colour me confused, my apologies if I've misread your post but isn't the LZOS 130/ASI183 (F6, 0.63"/px) significantly faster than the 10" RC/ASI16200 (F8, 0.38"/px), regardless of the aperture?

Actually, no. If we take 'faster' as meaning taking less time to acheive a specific SNR in an image.

Very useful calculator here by @dan_adi.  Plugging in the scopes outlined above and subbing in the 533 in place of the 6200 as it's not in the app database (same pixel size) you can see the 10" RC setup is faster than the 5" frac. Have to make some assumptions about reflectivity/light throughput.

http://clearskies.go.ro:8501/

Nice results, seeing been awful for me recently too, need some high pressure to pass over 

Very nice images! Yeah could try to deal with the ghosted limb by using an elliptical selection tool (just inside the disk), invert and feather it and then apply a slight Gaussian blur. That’s what i do when I get that artefact and it works well. 

53 minutes ago, neil phillips said:

Been waiting a while because of bad weather. Just got focus ready to capture. Sky completely clouded over. Anyway waited. And it cleared again. Which I didn't think it would.

Cheers for the positive comments Craig.

It’s absolutely spot on Neil the processing is just perfect to me. Bravo! 
 

Was thinking of having a go on Mars tonight if the forecast holds and was debating if I should go OSC or mono and you’ve just made up my mind… going to go with OSC.

Fantastic work Neil, best I’ve seen  anywhere yet this year. 👍🏼👍🏼👍🏼

45 minutes ago, ollypenrice said:

I've put this notion on 'hold' for the moment, Dave. The offset between focusers would be considerable so it isn't clear that an observer would be able to move easily between eyepieces. If that weren't possible there would be little point in having the small scope on the same mount.

Olly

You just need to find some EPs with 2ft of eye relief  

8 minutes ago, Trippelforge said:

 

I have been digging into spectrum ranges due to learning that modified DSLRs list out various options. I also noticed the IMX585 seems to cut off prior to falling into the UV range (via it's website graph). Another user in a post said:

 I don't see anything in the player one listing directly addressing that question. Any idea on the answer if the question is important?

That quote you referred to about OSC cameras is regarding the optical window in front of the sensors. It can either be AR coated only (let’s everything through) or it can be coated to reject UV and IR, which reduces star bloat especially in non-apochromatic optical systems.
 

The sensors behind them will be broadly similar in the wavelengths they can see, there will be differences between different cameras but not major differences, though saying that there are some OSC cameras that are particularly sensitive in the IR.

Mono sensors will normally be covered with an AR coated window which lets everything though. Again different mono sensors can have different sensitivities across the visible spectrum. 
 

17 hours ago, astrolulu said:

Rupes Recta, Cassini Bright Spot, Tycho... pick 'n' mix 🙂

 

This is fabulous, as is the previous ones. The expertly processed subtle colour really makes them stand out for me, not to mention the fine, clean detail 

18 minutes ago, vlaiv said:

why do it then?

I think there are a couple of reasons why you would choose to use a longer FR (but I’m not saying that these are the reasons why it is done by many)

1) Steeper light cone leads to reduced aberration due to ADC prisms (we touched on this a few weeks ago). Though I admit I don’t know how to quantify the ADC aberration at various FR in order to compare it to the loss of SNR between those FR.

2) More barlow power  = larger diffraction limited field diameter = Beneficial for collimation as more tolerance to any sag/droop in imaging train? 
 

Considering the large aperture scopes (and sensitive latest cameras) that most planetary imagers use bring in a lot of signal to begin with anyway so throwing a little away to get the above benefits could be a good decision? 

It’s not true lucky imaging as that requires exposures of a fraction of a second (to properly freeze the seeing) but it is kinda like a halfway technique.

Mostly used by owners of big scopes whereby the mounts required for normal long exposure imaging would be hideously expensive, so instead thousands of short (~1sec) images are captured and stacked.

These short exposures are too long to really freeze the seeing but the May help to reduce the seeing blur to a certain extent (depends on what the seeing is like - high frequency or low frequency blur) and also helps to avoid tacking errors, oh and guiding isn’t generally required.

The downside is you need a big fast scope  to get enough signal in such short exposures. Saying that though the release of the latest gen ultra low read noise cameras certainly makes it an attractive technique and certainly worth trying if you fancied having a go with the brighter targets

I wonder if oversampling helps by making the finest detail captured physically larger in the image than the pixel scale shot noise.

If the smallest details the image contains are larger (occupy more pixels) than the noise, then does that make it easier to sharpen the detail without sharpening that noise? 
Conversley if the smallest details are only occupying two pixels (if properly sampled) then does it become more difficult to then sharpen that detail without also sharpening the pixel scale noise as they are much closer in size? 
 

I’ve always sharpened my stacked tiffs first, mainly because I find it easier to place the image measurement outline frame around the planet on sharpened images, and an accurate measurement is critical for image derotation. 
 

Sorry not a Tak expert, but have you seen this? Where is the observatory located? 
 

Ah ok, I see lots of entire rigs for sale on here as a job lot but don’t often seeing them sold that way, more often the seller ends up splitting.

Could be worth speaking to a dealer who could take the whole lot of your hands? 

15 minutes ago, swag72 said:

OK thanks for your thoughts 👍🏻 I was thinking that the CCD tech may be harder to shift.

I'm at a bit of a loss for gauging price on a scope that is no longer made and I believe could be a decent one and rarely come up for sale. 

I guess if you’re really unsure and you’re not looking for a quick sale then start high (perhaps close to what you bought it for if you bought it new) and then lower the price gradually until it sells.

3 minutes ago, tooth_dr said:

trends have changed eg CCD versus CMOS.  

Very good point… some nice CCDs on here have been struggling to sell despite being very capable cameras. 

General rule of thumb is 2/3 of new price as long as item is in good condition with box and instructions etc etc. 

However there is a lot of variation on this:

Item condition, bits missing, current availability/rarity, willingness to post, etc. all can affect how much you get for something. 

Once you’ve got your Jupiter image size in pixels and it’s apparent size in arc seconds, plug it into the calculator here (6th one down)

https://www.wilmslowastro.com/software/formulae.htm

IMO there’s no way you’ll be able to swap one OTA for another and maintain an accurate PA, just the act of changing the tubes over is going to disturb it. You PA first when the mount is loaded up and when you unload it by taking weights/tube off and the mount is going to mechanically rebound (for want of a better word), next OTA goes on and the mount won’t then settle back into exactly its previous position. That’s my thoughts anyway. 
 

If you think about heave of the soil during dry/wet spells, thermal expansion/contraction of all the metal parts of the pier and mount, not to mention the concrete itself (CoTE of concrete is roughly the same as steel - depending on the aggregate used) and it’s no wonder that the most carefully adjusted PA doesn’t last long. 

44 minutes ago, ollypenrice said:

I'd have thought that, if you used a blowtorch on a spring, you'd change its metallurgical temper and, potentially, ruin it. I'm sure someone with metallurgical knowledge could give us chapter and verse but I wouldn't be too casual about heating a spring, myself.

Olly

Yeah probably. If I was working on a valve spring for an F1 engine I’d be concerned about that but for a collimation spring in a budget amateur telescope it works fine…. My springs are still very springy. 

They’re really good considering the equipment, nice work 👍🏼

Those are three sub-forums of the buy & sell forum area, you need to click into the top one and create your topic in there (and also view the sale ads in there too)

You’re talking about cone error, Google conesharp it will help you minimise it

Nice shots, very interesting to see how the small pixel/ lower FR setup works, very well by the look of it👍🏼