Trippelforge

3 hours ago, Vroobel said:

What software do you use for processing your data?

PixInsight 

11 minutes ago, ONIKKINEN said:

Rejection when stacking will remove them easily. There could be a hundred trails in total and none will be visible in the stack at the end.

DSS has kappa-sigma clipping which works well with a modest number of images (a few dozen at least to get the best result). Siril has winsorized sigma clipping that does the same thing. Siril also has the Generalized extreme studentized deviate test (awful name) method, which is very good with a large number of frames, think close to or more than a hundred. At the end of the day satellite trails are meaningless in subexposures and get rejected.

For every rejected frame it's "X" amount of data loss, that's what I am confused about. But perhaps I am not understanding things correctly. Say I take for example an hours worth of images at 5 minutes each, that's a total of 12 images (obviously). But if due to the longer exposures it caused me to lose say 4-5 images I just lost 1/3 of my data. 

On 13/03/2024 at 17:36, Stephen196360 said:

Hello mate

I'm steve 

And I could probably repair and repot

Or replace the broken parts

I'm a dab hand with a solving iron 

As I've chipped Playstation consoles and the lije for 40 years

So if you want to get in touch 

I'd be happy to advise etc

Kind regards steve 

Or contact me on

<private contact details removed>

Hi Steve,

Luckily I can solder, but thanks for the offer!

2 hours ago, symmetal said:

It's odd that Switchcraft do 2.0 and 2.1mm versions as they are so similar, and 2.1mm is a much more common size for DC connectors. However, if you click on the 'Datasheet' link on the 2.1mm connector you linked above it says the centre pin is 2.0mm just like the datasheet for the 2.0mm connector you posted earlier. The centre pin is split and spread slightly to provide a good contact when the plug is inserted so I think a 2.1mm or 2.0mm plug would connect fine in either situation. The L722A part in the connector name of the three versions you linked to has a 2.0mm centre pin, so one saying it's 2.1mm implies a 2.1mm plug works fine in a 2.0mm socket, due to the 2.0mm pin being spread apart.

In that case you may as well get the first one you linked to as that is intended for wire connections, while the other two are intended for PC board mounting. Clicking on the datasheet for the connector you choose shows which pins you want to connect your red and black wires to, red to centre pin and black to sleeve, leaving the sleeve shunt unconnected.

I think that the xL722x series of connectors are Switchcrafts version of the common 2.1mm connector, with a threaded sleeve, and their xL712x series are their version of the common 2.5mm connector, with a threaded sleeve. 🙂

Alan

 

Thank you so much Alan, I really do appreciate your help! Things started to get a bit confusing for me (obviously).

I am going to order the first one, L722A as you suggest, excited to get the mount back up and running!

21 hours ago, symmetal said:

They are both in fact panel mount, the difference is that the PCL722A is to fit directly on a PCB (through hole) while the L722A is intended to connect to wires so the L722A would be the better choice in your case.

Don't worry about them having three pins on the connectors. It looks like your original photo just has the third pin cut off anyway. It's common to use these connectors in battery powered equipment with the option of external power. The battery +ve goes to the third pin and with no external power plug inserted it's connected to the red +ve wire. When you plug the power plug in it breaks this connection and the battery is disconnected, and the power supplied externally. As there is no internal battery in your situation you can ignore the third pin.

Alan

Someone told me they think the actual plug is 2.10 not 2.00mm, the only thing Digikey has in 2.10mm is this: 

https://www.digikey.com/en/products/detail/switchcraft-inc/L722RA/1289482

It looks kind of odd though due to the angle of the pins. Is there a way for me to check the plug, for instance if I used a gage pin for the inside, and calipers for the outside does that give you exactly what it's suppose to be? That's probably a dumb question, but I want to make sure it's a perfect fit. 

Thanks for the help!

5 minutes ago, Tomatobro said:

try this     https://www.digikey.com/en/products/detail/switchcraft-inc/S761K/1289494

 

 

That's the end that pushes into the hole correct? I need the receiving end that is attached to the mount. 

I found this, there are few styles listed, not sure of the difference as the images look the same, one says panel mount, the other through hole.

Do you think this is the correct part?

https://www.digikey.com/en/products/detail/switchcraft-inc/L722A/241928

This is the other: https://www.digikey.com/en/products/detail/switchcraft-inc/PCL722A/1289408

Anyhow they both have three leads? There are only two wires going to the board.

51 minutes ago, Tomatobro said:

There is a post on Cloudy Nights that claims to have found the bulkhead socket. Here is the link to the supplier

Switchcraft S761
https://www.digikey....C240-ND/128949

It is 5.5 mm o.d., 2.0 mm i.d.  

digikey is available in the USA

Can you share the full link, it seems to have cut off the complete URL. 

Ugh what a pain though, you would think Celestron could simply sell that part. So you are saying worst case I can rig something up as long as it fits the male end of the power supply connector? And I assume solder on the little wires attached to the connector?  

The bulkhead if I know what you mean is what seemingly broke, but if I could've gotten the entire unit (with board connector) it would've been plug and play obviously. 

Thanks for the help!

Hey guys!

Last night I went to plug in my AVX and the power plug ended up getting stuck and broke the internal connector. I tried searching awhile for simply a replacement, but came up empty handed. I was a bit relieved to find out it was a fairly simple plug and play part (not soldered), but regardless it doesn't come up during searches.

Can anyone help me out? Thank you!

I just wanted to share my sons image of the Bubble Nebula. He is 15 and we have shared the hobby for a few years, but this image he did all on his own from start to finish. I am very proud of his final result!

Thank you very much! I do not own a flattener, it's good to know about the distance so I can tweak one to get it correct.

My son and I imaged the bubble nebula last week and once processed I noticed the outer edge stars "streaked". Considering the ones in the center are sharp, I assume it wasn't a tracking issue. Are the images coming out like this due to needing a flattener? Or could it have been caused by something else? Thanks!

I'm about to buy a mini-PC and wanted to grab a portable monitor for it. But something I didn't think about was how well they would work in cold temperatures. I had been using a laptop, and frost would form on it without issue. But with winter quickly approaching things are going to get a little rough here. When the thought popped in my mind I went out and did a bit of research and found you aren't supposed to use LCD's or LED's below freezing. I mean I guess the entire "liquid" part makes since. But I know people shoot below 0'C outdoors with computers, so I figured I should ask what everyone's thoughts / experiences were.

4 hours ago, fifeskies said:

Simple answer is yes.

Anything that can move position will cause errors , always make sure everything is well tightened up , not to the point of damage , but should have no movement.

 

That said I dont expect a short time like 2 minutes would be likely to move the mount enough for the bar to suddenly slip position , not on every sub at least, more likely to only cause a shift every so often.

To see a drift after only 15 seconds suggests there may be some othe cause.

What method were you using to polar align?

I dont set up each day as I now have a mount on a pier , but in the past I have misidentified an alignment star and so had a lot of drift after alignment.

My error made the mount think it was well aligned when it fact it was nowhere near the celestial pole.

I was hoping that was all it was. I am using Celestrons "all-star" alignment procedure. I tried it with and without prior go-to alignment, it worked night one and two, but wouldn't night 3. I even was able to rough align via polaris in NINA's cross hairs night one and it "sort of" worked on it's own. But then I ended up running all-star anyhow. I asked my son if he entered in or double checked the coordinates and time. He hesitated then said yes... makes you wonder though. =P

I did find two guides, one by a user and another very detailed one in an article. I am going to make sure I go step by step and so I don't miss anything. If that doesn't work.... well maybe I was one of the ones who's AVX's didn't make it through QC. What kind of sucks is my son and I are driving 3hrs away Saturday to camp and image in a remote area. It's going to be freezing also... so this should be fun.

3 hours ago, Seelive said:

From your description I take it you are not guiding so then I can only assume that your exposure time is dependant upon the accuracy of your polar alignment.  So how do you polar align?  If you're using a polarscope with the mount just set in the home position then a wobbly counterweight won't make any difference.  If the polar alignment requires slewing the mount then a wobbly counterweight could affect the position of the scope in certain orientations if you have backlash or stiction in one or more axes which could then affect the polar alignment calculations.

I used all-star polar alignment (Celestron) a few times (slewing all over). I also did so before and after a go-to alignment just for fun. I even "aligned" it via NINA's crosshairs before just to get close. Worked great as I mentioned! But... now I don't know what's going on. Defective? Missed something? I am going to hope that it was just my failure to turn a rod.  

Due to the frustration I ran into last night, coupled with the fact I won't be able to get out for awhile. I wanted to ask this simple, albeit pretty dumb question. I have taken my new mount out 3 times now. Night 1 & 2 I was able to get the polar alignment dead on and had zero issues with tracking. Last night I spent an hour trying to get it to track longer than 15 seconds and couldn't. On Night 1 & 2 I was getting around 2 minutes with it locked on, and didn't even try any longer. Once I took my mount in last night I notice when replacing the counter weight that the bar was wiggling, as it seemingly at one point unscrewed itself a bit, so I am thinking it was loose the entire time I was aligning it.

The obvious answer is to go shoot again, but it might be awhile. So I wanted to ask if that could've been why I was having issues?

Thanks 😃

6 minutes ago, vlaiv said:

It really depends on what data are you trying to calibrate.

I'll assume the following:

- you have DSLR

- your DSLR has automatic dark current removal. You can test this by taking two darks. One very short (say one second) and another rather long - say 30 seconds or so. Both images need to be true darks. Try to avoid any light leak or even IR leak (infrared can penetrate plastics). On DSLRs, be sure to use viewfinder cover to block any light getting in that way.

Best to take subs in very dark room without any light.

Once you have your subs - open them in any software that loads raw files and gives you access to raw data and simply measure average ADU value of them. If both subs have same average ADU value - you have automatic dark current removal (otherwise average ADU value of longer sub should be higher as it has more dark current signal).

If above is all true - then calibrate as follows:

- shoot lights

- shoot bias (which are darks at minimum exposure length)

- shoot flats

- match ISO setting between all three. When shooting flats - avoid clipping. Histogram should show three nice looking peaks at the center or 2/3 to the right.

Stack bias to master bias

subtract master bias from every flat and every light

Stack flats (with bias removed) into master flat

Divide each light (with bias removed) with master flat.

Ideally, software that you are using should do above for you if you provide it with said files automatically.

Thank you! That really cleared things up for me. I haven't ever even seen anything say an ADU rating before. Is that in the RAW image properties itself? Or do I need to open it in specific software?

Anyhow I appreciate all of the help, and thanks for taking the time to break it all down. 

3 minutes ago, vlaiv said:

 

If you are using DSLR - you can just use bias as there is dark compensation thing happening in the camera (most modern sensors do this).

So simply shoot bias frames, no darks or flats? Ugh, sorry I am getting confused as this entire thing is much more complicated than I at first thought. 😃

17 minutes ago, WolfieGlos said:

As a fellow DSLR user, this is what I do:

1) Ignore darks. They can make a difference though if you are not dithering. A lot of people say you can be within 5 degrees of the lights temperature, and I found this to be true. They actually masked walking noise that I was suffering from early on. I once used 30 degree darks with 15 degree lights….it was not a pretty sight!

2) Bias, set your camera to the same ISO, fastest shutter speed (mine is 4000th second), put the lens cap on and shoot away. I always use ISO 400, and I’ve used the same files for the past 12 months. I have 50 of them.

3) Flats - put your camera on Av mode, using the T-shirt, flat panel, etc and shoot away. I used to use 50, but have been using 35 lately and notice no difference. Although technically you aren’t supposed to use them more than once, I keep my scope and camera in the same setup and use them across a few sessions. Usually I change after 3 or 4 sessions. 

I don't dither right now as I don't know how. I know what it is, but software wise I am unsure on how to control it. I have one program (by Celstron) to move the mount, and I use NINA to control everything else. I guess I need to dig more into that as Vlaiv pointed out that they aren't re-usable due to temperature fluctuations. 

AV mode? You shoot it in video?  

15 minutes ago, vlaiv said:

No, they don't eliminate the noise - they eliminate dark current signal. Noise remains in the image.

They are reusable only if have set point cooling and can reproduce temperature.

If you use them, bias files are not necessary as bias signal is contained in dark subs

That is pretty much correct - include flat darks for best results (darks that match flat exposure and which you subtract from flats).

Flats are reusable if you have permanent setup or have electronic filter wheel with good repeatability or OSC sensor and you don't dismantle your optical train. If you for example pack after each session but leave the scope and camera attached as a single unit - you can reuse flats

Calibration files don't remove noise - they remove signal. Bias files remove bias signal and they can be used if:

1. You have modern DSLR that has dark subtraction built in. This will remove dark current without bias so you manually have to remove bias afterwards

2. You plan on using dark scaling / dark optimization when calibrating subs

3. You use very short flat exposures then you can use bias files instead of flat darks

I advocate use of larger number of calibration subs. As much as you can shoot without too much inconvenience.

Calibration subs don't remove noise - but they do introduce new noise in the image. More calibration subs you have - less new noise you'll introduce into final image.

So is it possible to use solely flats to get rid of some dust spots I have? I will be tight on time tonight but would love to get rid of them. Ya this entire thing is seemingly more complicated than I thought. The dark re-use situation makes sense... and it kind of sucks due to having to re-do that every night. =(

9 minutes ago, tooth_dr said:

You are only going to get more opinions here too though.

You have also missed out dark flats. These are used to calibrate you flats, similar to a dark but same time as your flats.

I’m not able to see what equipment you are using but if your camera has set point cooling then just keep the lights the same temp all the time and take your calibration data as the same temp (same gain, same offset, etc).

I use 30 of each type for my calibration data.  That works for me but I suspect I wouldn’t see any difference with 25 or 100 frames.

Flats imo are the most important calibration frame, they make processing a lot easier if applied correctly.

Take 30-50 of each.  Process your data and look at it.  Speaking from personal experience, the number of calibration frames won’t make any tangible difference, it’s what happens to the stacks afterwards where it all goes wrong (and occasionally right!)

Aren't dark flats most important with dedicated / cooled astro camera's (read that on a random blog)? I am shooting with a DSLR (Nikon D5300). 

Are you saying that the amount of frames really doesn't make that big of a difference? One question, how long of an exposure should each dark and flat be? I didn't see that mentioned anywhere. 

I have been imagine for a few years, yet have never taken calibration frames. It's just something I never took the time to do, perhaps due to laziness or maybe because I was happy enough with my images. But now that my son has joined up in the hobby with me, we want to hit the limits of our equipment. So I think it's time for me to actually take the extra steps for improvement.

With that being said I am getting FLOODED with information / opinions on how to deal with calibration frames. Over on cloudy nights there have been some heated debates on the amount of frames overall. And there is a HUGE divide... some are saying 15-20 darks, and some 200+... All I want is a simple metric to start with.

First of all am I understanding the reasoning behind each type?

1. Darks help eliminate noise, are re-usable, and you simply cap off the scope to take them. Also they should be taken at the same sensor temperature (and ISO) as the lights. 

2. Flats are for vignetting and dust spots. I need to use a t-shirt to cover the scope, and the images need to peak at the middle of the histogram. The imaging train cannot be moved afterwards, hence These are not re-usable. Also I have to use an even light source, or the sky at dusk / dawn.
 

3. Bias frames simply help read-out noise. Cap the camera or scope and take them as fast as possible, you can re-use them. 
 

If I am correct; how many frames do I need? And how long should each exposure be for each type?  

Apologies on the dead horse topic, I am just getting so many different opinions and wanted to ask here. 

I have been using my Nikon for awhile and really never was sure of the optimal ISO setting. Currently I am shooting at 400. I have read that Nikons over all perform better at lower ISO's than Canon's. But I am sure it's more model dependent. I had an old chart but it didn't have the D5300 on it. Thanks 😃

19 hours ago, Icesheet said:

Does anyone know the background of this table, how it is measured and how reliable it is? I was obviously aware of the hugely detrimental effect of light pollution but hadn’t really seen it set out numerically like this. That’s mind blowing to me and potentially hugely significant. According to light pollution maps I image from just inside a Bortle 4 zone. However, depending on the direction I image it can be towards B2/3 or B5/6. Given the significance of the apparent jump from 4-5, I wonder if my imaging time is better spent solely towards Bortle 4 and under. Could anyone suggest what I could do to test this?

 

Edit: Apologies, I see this is in an Observing forum. I can start a new topic in an Imaging forum if it’s preferable. 

It was shared on Cloudynights by a member, there was a graph as well. I believe he wrote up an entire paper outlining his methodologies (I will look for it). But he is seemingly a fairly well respected member so I just kind of went with it (lol). Anyways my mind was blown as well, I live in a bortal 5/6 zone and my son and I have been planning to go camping this winter to some 2/3 zones.  Which obviously looking at the chart is going to be insane.   

1 minute ago, John said:

I would pronounce it "Bor-tul" but spell it as @Floater suggests. 

I was surprised to learn that the scale has only been around since 2001 when John E Bortle published it in Sky & Telescope. Here is that article re-published by Sky & Telescope in 2008:

Light Pollution and Astronomy: How Dark Are Your Night Skies? - Sky & Telescope (skyandtelescope.org)

Funny enough I don't even know anymore HOW I was saying it due to you posting that. Bortle, bortal... ugh. Now I am all messed up...

16 minutes ago, drdre2030 said:

No expert...but the Bortal scale does use the NELM magnitude which is kind of what you are looking for I think, whilst maybe not brightness per se but is a scale. I think the difference between B2 to B1, B3 to B2 is not that big, B4 to B3 starts to make a difference, then each one after exponentially. 

I think as you say with things not being exact or outdated, trying to find reviews or people who have been to other places is probably a subjective, but informed way of trying to know if worth it.

Someone shared a few charts with me showing the various differences in exposure times, and you are right. It's pretty mind blowing how quickly it rockets upward. 

I have been making a list of camping sites via their projected darkness. I mostly stuck to simply the bortal rating of each, but then of course other measurements are presented. But from a simple standpoint I was curious if there was a brightness range that qualifies each bortal number.

For example;

Site 1: Bortal 4 @ .230 brightness
Site 2: Bortal 3 @ .190 brightness
Site 3: Bortal 2 @ .188 brightness

Does that mean that a Bortal 2 turns to a Bortal 3 at around .190? If so would that mean that the .188 site vs .190 are so close the rating is irrelevant?

Side Note: I do understand that the light pollution maps are not exact, and can be outdated. But I was just trying to get a general idea prior to driving across my state.

I am finding out fairly quickly that my new AVX really needs guiding. Which is a let down, but supposedly with guiding it can perform very well. The problem is that I have never owned one before, and I am very low on funds so I am trying to find something reasonable. I know "reasonable" is relative, but I need to know how low I can go, yet get one that's still reliable. I guess that goes also for a finder scope itself... which I just remembered. 

Thanks!