20 replies to this topic

[anrran]

Hi,

 

I'm not sure if this is the right place to post this or not, but I'm kind of new to astrophotography and this is a beginner forum after all. I've dabbled a little in the past but wasn't that serious about it. Since this quarantine is going on, it got me rethinking about it again (since I have nothing else to do), so I started researching equipment online. I live smack in the middle of Houston (pure white on the light pollution maps, not even antique white) so obviously my first research topic was light pollution filters. There seems to be many on the market these days and a few recommended by popular YouTubers like AstroBackyard, AstroStace, etc.so these are the ones I narrowed in on with my research. One thing that keeps annoying me though is the pictures of the spectrum of these filters suck most of the time and it's somewhat tiresome flipping between different websites to compare them. Even then, figuring out where the peak of one filter is in relation of a similar peak of another filter is gets confusing.

 

So in my boredom and imprisonment at the moment I downloaded a program called Graph Grabber which can take pictures of graphs (i.e. LP filter spectrum pictures) and turn them into data points that you can plot in any plotting software (in my case, Excel) that you have. Basically you click on the min and max points of the x and y axis of the picture, then you click at various points along the spectrum. The program uses all your clicks to create data points that you can export to a file, which then you can plot in Excel. I did this for all the popular filters currently on the market so that I can compare them without flipping to different websites. However, the plots are only as accurate as the quality of the picture I used (in some cases terrible, surprisingly more so the more expensive the filter) and my clicking prowess (which is "impeccable", unless it's 1 am in the morning). Attached is an Excel document with the spectral graphs plotted (solid lines) alongside the most common light pollution sources (dashed lines) and emission spectra (dotted lines). I created three graphs each, one for Duo, Tri, and Quad band filters; one for multi spectral filters; another for generic light pollution filters. These are separated by three different tabs in the spreadsheet (just click on what tab you want to view). I also have all filters for each graph showing, which makes it super convoluted. You can turn whatever ones you want on or off by clicking on a white space in the graph, select Design under Chart Tools in the top ribbon, click Select Data. A menu pops up with check marks next to filter names; just uncheck whatever filters you want to remove from the graph, and click Okay. The plot should update to reflect your changes.

 

Duo, Tri, Quad band filters:

Altair Astro Quadband

Altair Astro Triband

Hutech IDAS EAO1

Hutech IDAS NB1

Hutech IDAS NB2 + NGS1

Hutech IDAS NB3 + NGS1

Optolong L-eNhance

Radian Triad Triband

Radian Triad Ultra

STC Astro Duo Narrowband

 

Multi Spectral filters:

Hutech IDAS LPS D1

Hutech IDAS LPS D2

Hutech IDAS LPS P2

Hutech IDAS LPS NGS1

Optolong L-Pro

Skytech L-Pro Max

STC Ultra Layer Astro Multispectra

 

Light Pollution filters:

Altair Astro CLS

Astronomik CLS

Astronomik CLS CCD

Astronomik UHC

Astronomik UHC E

Hutech IDAS LPS V4

Optolong UHC

Skytech CLS

 

I'm not sure if anyone did this already, but I couldn't find anything when I searched for it. Hopefully this will help some of you to choose the correct filters you want to buy. And if there are any mistakes, it's not my fault....

 

Regards,

Aaron

 

 

 LP_Filter_Spectral_Comparison.xlsx   165.06KB   833 downloads

[TelescopeGreg]

Thanks for doing this!

 

Question:  Is there an "easy" way to enable / disable the individual filters, to untangle some of the graphs?  Editing the data ranges can work, but it's kind of clumsy...  (I'm using LibreOffice, by the way.)

[anrran]

Hi,

 

Unfortunately, I am not really familiar with how LibreOffice works. I did just download it to play around with it. The only thing I can find so far is to just delete the plots you don't want from the data ranges, but like you said that is not ideal especially if you want to bring them back up. I don't see an option like in Excel to just check or uncheck them. You could also right click on the line you want to "remove", click format series and change the transparency to like 75% or something so it almost goes away. Or change the line color to white. Trying to click on the line to find it again is kind of difficult though. Maybe someone with more knowledge on the software than me could chime in. It does seem like a basic function that the software should be able to do. Sorry I couldn't help much.

 

-Aaron

[anamik]

This is so useful. I am trying to decide between the IDAS NGS1 and LPS D2 and the plots make the analysis a lot easier.

 

Thank you!

[blemasle]

Wow ! Thank you for taking the time to do it, and to share that work afterwards !

It is of great help

[BABOafrica]

>>A menu pops up with check marks next to filter names; just uncheck whatever filters you want to remove from the graph, and click Okay. The plot should update to reflect your changes.<<

 

Quite nifty feature. But I could not figure out exactly how it works.

 

How do you get the MENU to "pop up" ???

 

Joe

[jerr]

Hi Aaron,

 

Is there a chance you add Optolong L-eXtreme data to the chart?

[Marc Sudhof]

Very nice! Thank you so much! 

[TNGary63]

>>A menu pops up with check marks next to filter names; just uncheck whatever filters you want to remove from the graph, and click Okay. The plot should update to reflect your changes.<<

 

Quite nifty feature. But I could not figure out exactly how it works.

 

How do you get the MENU to "pop up" ???

 

Joe

Maybe old info by now.   Right-click on the chart, then go down to "Select Data".  You can turn off and on the filters, also the Ha, Oiii, etc. lines.

 

Gary

[anrran]

Hi Aaron,

 

Is there a chance you add Optolong L-eXtreme data to the chart?

Hi Jerr,

 

Sorry it's been a while since I logged on to this site. I added the L-eXtreme to the spreadsheet attached in this reply. It is on the Duo, Tri, Quad filter tab. I hope it helps if you haven't already purchased a filter.

[anrran]

>>A menu pops up with check marks next to filter names; just uncheck whatever filters you want to remove from the graph, and click Okay. The plot should update to reflect your changes.<<

 

Quite nifty feature. But I could not figure out exactly how it works.

 

How do you get the MENU to "pop up" ???

 

Joe

 

 

Maybe old info by now.   Right-click on the chart, then go down to "Select Data".  You can turn off and on the filters, also the Ha, Oiii, etc. lines.

 

Gary

Hi Joe,

 

Gary is correct, also you could click on the Chart filter button (bottom of the three buttons on the top right of the graph; top is a plus sign, the middle is a paint brush, and the bottom looks like a martini glass without the base). Then you could check whatever filters you want. See the attached photo.

 

-Aaron

[anrran]

Sorry I forgot to attach them in my previous posts.

Attached Thumbnails

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Attached Files

•  LP_Filter_Spectral_Comparison_v2.xlsx   169.58KB   182 downloads

[Jinux]

This is unbelievably super job! Thank you very much!

 

Is there any chance you made a mistake on "Radian Triad Triband"? Transmission graph has value bigger than 100 which is questionable.

 

-Jinux

[anrran]

This is unbelievably super job! Thank you very much!

 

Is there any chance you made a mistake on "Radian Triad Triband"? Transmission graph has value bigger than 100 which is questionable.

 

-Jinux

Yea I guess I clicked a little higher than needed on that spectrum to get that point. The picture from the website has it at 100 though, so it should be at 100 I suppose.

[jerr]

Hi Jerr,

 

Sorry it's been a while since I logged on to this site. I added the L-eXtreme to the spreadsheet attached in this reply. It is on the Duo, Tri, Quad filter tab. I hope it helps if you haven't already purchased a filter.

Aaron,

 

Great thanks - highly appreciated!

[anrran]

I noticed some of the Optolong and Radian Filters in the Duo,Ti, Quad tab were slightly off so I made some edits to them. Attached is the updated document.

 

-Aaron 

Attached Files

•  LP_Filter_Spectral_Comparison_v3.xlsx   231.74KB   381 downloads

[SteveInNZ]

Does anyone have a third party XLSX viewer that shows the filter selection panel as above ?

I have an early version of Excel, Open Office and tried the MS and a free third party viewer but still no luck.

 

Steve.

[TelescopeGreg]

Does anyone have a third party XLSX viewer that shows the filter selection panel as above ?

I have an early version of Excel, Open Office and tried the MS and a free third party viewer but still no luck.

 

Steve.

It opened fine for me in an old copy of LibreOffice, v5.2.5.1.

[SteveInNZ]

LibreOffice is the same as OpenOffice in that it doesn't give you the checkbox options (see post #12) that makes it easy to turn plots on or off. You asked the same thing in post #2 above.

 

Steve.

[GeorgeLiv]

Happy New Year to all!

 

I must say the xls is very good, nice job. But it can be improved further:

 

To reduce clutter the Hg spectral lines should be vertical dashes without bandwidths.

The HPS spectrum should also be more spiky (569nm is more of a line).

You are missing the major scandium lines but at least you got LED in there.

The LED blue peak should be closer to 450 nm and both phosphor and blue crests should be at about equal heights (for neutral and warm toned LED systems). This would be in line with what was installed out there after 2016.

You have the LED trough (depression) very close to where it always bottoms out (around 486-489 nm, yes, pretty much where the Hbeta line is located)

 

Other than those points the collection is very fun to browse through!

Edited by GeorgeLiv, 01 January 2021 - 06:10 AM.

[Craigar]

Is there any easy simple NON MICROSOFT way to open this in a free online app (not Microsoft)  or "offline/download and install app" that can use a checkbox to turn whatever ones you want on or off, like you explained here (when using MS Excel licensed version)

You can turn whatever ones you want on or off by clicking on a white space in the graph, select Design under Chart Tools in the top ribbon, click Select Data. A menu pops up with check marks next to filter names; just uncheck whatever filters you want to remove from the graph, and click Okay. The plot should update to reflect your changes.

this is supposed to edit online but I couldn't figure out how to do what we want here
https://products.aspose.app
 
 
thanks everybody!