Nikodemuzz

Thanks Magnus! This is true, however, here my problem is that I'm getting wrong Boolean results. Excel gives me a list of all FALSE to an ISBLANK query, while there are blank cells present. Or counts 24 non-zero cells, even though there are zeros present.

I was hoping that I would have had my ducks in a row to complete my mighty spreadsheet, now that the aforementioned problem was solved. Alas, it wasn't meant to be. It seems I have run into another conundrum. Who knew! Hopefully you can again lend a hand! At the moment I am building the calculation that computes the elevation of the targets in the sky at chosen moments. As I am building a yearly calendar, I have simplified things by choosing only one day from each month to study. For these dates (always the 15th) I'm calculating the hourly elevation of the targets. As I'm only interested in the points of time when it is dark enough to observe, I have also calculated the local hourly elevation of the sun. Then, the local times must be converted to standard time, or sidereal time. As a result I get a table of sidereal times for the moments when it is dark, like so: As a next step I want to solve the monthly highest elevation for each target. My thinking was that using the above table I could handily exclude the times when it isn't dark. Following this step I could categorize the targets into tiers based on their monthly highest elevation. In order to find the monthly maximum elevation I have tried to use the following formula: {=MAX(DEGREES(ASIN(SIN(RADIANS(P2))*SIN(RADIANS(Variables!B3))+COS(RADIANS(P2))*COS(RADIANS(Variables!B3))*COS(RADIANS(IF(('Sidereal times'!$B$3:$B$26-Catalogue!K2)<0;('Sidereal times'!$B$3:$B$26-Catalogue!K2)+360;('Sidereal times'!$B$3:$B$26-Catalogue!K2)))))))} Inside the MAX function is the elevation calculation that uses the observation latitude (Variables!B3), target coordinates in RA (K2) and DEC (P2), and the sidereal time. The idea is to use MAX to find the sidereal time that produces the highest elevation. The MAX function normally excludes blanks, but in this case I get a #VALUE error from my formula. If I limit the range to only the non-blank cells (ie. B1:B10), it works. Now, if I examine the blank cells with COUNTIF, IF, ISBLANK etc to see how Excel perceives the blank cells, it in fact does not consider them as blank (ISBLANK returns FALSE). Similarly, if I tell it to output 0 instead of blank into the cells when it is not dark, I find some strange behaviour. Excel can correctly count 9 zeros from cells B9:B17, but if I ask it to count non-zero cells ("<>0") from B3:B26, I get 24. At least to me, this makes it hard to exclude them from the calculation with logical functions. Could anyone offer some advice as to how can I get the calculation working, while fulfilling the target of not taking into account the times when it isn't dark enough to do observations?

Thanks for taking the time to write out an example, kudos! I can follow along your code and understand reasonably well what is happening. Applying it myself is another matter, daunting being a rather good word to describe the thought. Edit: typo

This was the solution, thank you very much!

Haha, touche!

Your suggestion of putting the TRUE/FALSE in a separate column could actually be the perfect workaround to the problem, thank you! To help everyone understand a bit better what I'm trying to do, I'll explain the background a bit more. In "Sheet1", I have the NGC and IC catalogues of objects with their positional and apparent size data. In "Sheet2" I have calculated the fields of view I get with the desired combination of telescopes and cameras. Let's say these are FOV1, FOV2 and FOV3, with FOV1 being the largest. In "Sheet3" I'm compiling a list of objects that are suitable for each telescope/camera combination. The formula I gave above as an example compares the apparent sizes of the objects to FOV2, and if it is larger, adds the object name to the list. The ultimate objective of this excercise is to have tool that shows you what objects are the best to shoot with your available gear, in your location, divided monthly.

This is exactly the problem with vlookup in my case. I'm not proficient with VBA, so I have been trying to avoid it. Could well be that I have arrived to the point where I no longer can.

This might work, although the problem is not with the comparisons, it is with the AND function which I would still have to use in this case.

Thanks for the suggestion! If I understand correctly vlookup has restrictions in this case. I'll explain further in a subsequent message.

I'm not sure if this is the correct place to ask this, but I hope I might get some assistance with Excel. I'm building a tool for astrophotography planning. I'm planning to share it with the community, provided I manage to finish it! 😃 The Excel problem I'm having is the following: I'm compiling a list of data in Sheet3. In order to do that, I'm comparing values in a table (Sheet 2) to a dataset (Sheet 1). I check if the values in a certain column in Sheet 1 match the criteria set in Sheet 2, and if so, return a value from another column in Sheet 1. This works well as long as I have only one criteria to check. The problem arises when I need to check if the reference number is between input values. In other words, check if the value is in a set range. I have discovered that the AND function does not work with arrays. If I input my formula as "not an array", it works fine. I have tried to get around the AND function by multiplying the conditions, but get the same result: works as a normal formula, not as an array. I am at a loss as to how to proceed. Could anyone offer some advice? Example of the formula using AND: =IF(AND((Sheet1!V2>Sheet2!$D$5);(Sheet1!V2<Sheet2!$D$4));"TRUE";"FALSE") Example of the formula not using AND: =IF((Sheet1!V2>Sheet2!$D$5)*(Sheet1!V2<Sheet2!$D$4);"TRUE";"FALSE") Example of an array formula not using AND, that doesn't work: {=IF((Sheet1$V$2:$V$12539>Sheet2!$D$5)*(Sheet1!$V$2:$V$12539<Sheet2!$D$4);"TRUE";"FALSE")} The previous examples describe the logical test, which is the problem area in my formula. The complete formula is larger. Example of the complete formula that works (only one criteria): =IF(ISERROR(INDEX(Sheet1!$A$2:$A$12539;SMALL(IF(Sheet1!$V$2:$V$12539>Sheet2!$D$4;ROW(Sheet1!$V$2:$V$12539));ROW(Sheet1!1:1))-1;1));"";INDEX(Sheet1!$A$2:$A$12539;SMALL(IF(Sheet1!$V$2:$V$12539>Sheet2!$D$4;ROW(Sheet1!$V$2:$V$12539));ROW(Sheet1!1:1))-1;1)) Sorry for the long post!

It probably will, but it's all relative. With the zoomable live view, for example, focusing is still so much easier than it was before those features! Let alone using film. We are spoiled with all kinds of cadgets and software these days, and the do increase the chances of success considerably, especially for a novice. You can still get outstanding results without them, too. One just has to put more effort into knowing their equipment and how to use them.

The current mount has performed well. My previous CGEM sounded like it was about to give up in the cold, even after servicing it. The CEM60 doen't seem to mind. Granted, it is getting off rather easy at the moment since it is only carrying the SpaceCat. Guiding errors might be unnoticeable too with the short focal length, but I haven't seen any problems so far. All the cables stiffen up, but it hasn't caused problems. I have installed everything in a way that nothing is hanging off the telescope, and no cables should be moving during operation.

I started out with my Fuji (X-T2 and later X-T3), but acquired a dedicated astro camera last spring. The main reason was not the sensor performance, but the lack of support by the usual astro utilities that can be of great help, focusing and controlling the camera from your laptop or even phone. In terms of image quality, focusing will be the biggest challenge if you have only the camera to use and no aids, in my opinion. Here is a link to one of the photos I posted here, taken with the X-T3:

That´s the upside, yeah! 🤣 On 10min exposures the cooler on my camera barely starts.

Something like this is pretty much the norm for us up here in the Nordics. I envy those who can observe in comfortable conditions year round!

I hear you! However, if the Takahashi TSA-120 is double the price of the Esprit 120, the TEC 140 is roughly double the Takahashi! The reducer alone at 1900€ is almost as much as the Esprit 120. I was able to present this investment plan to the better half in such a way that she recommended that I go for the Takahashi, but I'm not sure my rhetorical skills could raise the bar enough to reach TEC prices. 😬😅 Used? Yes, absolutely, if only I could find one!

Thanks for the input! Yes, the Esprit 120 would be easy enough to handle, I'm sure. The difference between it and the 150 is pretty substantial. 😃 The optical quality seems to be up there also, certainly not large enough to warrant the price difference. I have to admit that the main reason for leaning towards the Takahashi is a sentimental one. Since a boy I have seen pictures of Takahashi telescopes in books (and later online), and the best images seemed to often have Takahashi written in the captions. Owning one was never an idea I could realistically entertain until now, although it was a dream. So there would be a special feeling in using a Tak. Whether that feeling is worth paying double is another, very subjective matter. I'm still not quite sure for myself, but it's a definite maybe! 😅 Another twist in this story is the shortage of equipment at the moment. For the Esprit 120 the estimated delivery time goes deep into spring, meaning that it's quite likely I wouldn't get to use the new scope until next season anyway (no darkness here in May-July). A bit more time to save up then, if I so choose. If this wasn't the case I probably would have already placed an order for the Esprit and probably would have been very happy with it for the rest of my days. 😃

I'm resurrecting this thread, as the process is still underway for me. Hopefully reading how my thought process has evolved will be of interest and perhaps even helpful to some! I haven't been active on the market since posting last time. I let the matter boil on the back burner of my mind during the summer and the earlier half of this season, and have come to a couple of conclusions: - First, I'm going to be buying only once. This means that I'll consider only models with proven track record, meaning Takahashi, AP, TEC, etc. Also the Esprits are very highly rated, so they make the cut as well. - Second, usability is key. This season I can count the clear nights in my neck of the woods with fingers of one hand. I don't want to lose any observing or imaging time because the setup is too tedious or tricky. Also, I have to be able to set up and dismantle alone in the snowy/icy backyard when its -30C without hurting myself or the equipment. On this note, I have ruled out the Esprit 150 and others in its weight class as too cumbersome. I have started to gravitate towards the Takahashi TSA-120 as the sweet spot for me, given its compact nature and optical quality. The TEC140 is also lighter than many others in its size bracket, but buying new it is out of bounds for me price-wise. I placed a wanted ad for these scopes, maybe something will pop up! I'm not in a particular rush, but would like to have a new refractor for next season.

I see now. The problem is that the ASIAIR is playing the part of the computer, but resides on the wrong end of the mount's USB hub. If I move the ASIAIR off the scope and on the mount and connect all accessories through the mount, it should work. Thanks @stash_old and @kens for taking the time! @kens You are right, it was wrong of me to say that there is no practical application for that kind of connection. What I meant is that connecting the cables that way doesn't make sense in my case (if the ASIAIR is on the scope)

1. No, it is a USB-B, the odd square type. Guide port is next to it, but not visible in my photo. See here: 2. Correct, however it is built in as a one cable 3. Correct 4. I'm not sure, but I think so. I can't see the cables working in one sequence but not in other if this was the case.

OK, so scenario 1. This works, and this is how I have been operating. However, this means that there is a potential cable snag issue with the cable coming from the ASIAIR (which sits on top of the scope) to the mount. The mount has a built in system to eliminate this problem, and I would like to use it. Scenario 2: This is how the built in system should work, but it doesn't. Scenario 3: For some reason if I go through the USB hub the other way around, it works. This has no practical application, but it proves that none of the components are faulty? Hopefully it will now be easier to understand what I am describing. 😃

You could be right about the USB identification, as ASIAIR actually mentions something about a change in camera connections when I connect the mount and it doesn't recognize it. How could this be solved if this is the case? I don't think it's a power issue. The mount has its own power, and the rest of the equipment are powered through ASIAIR. I'll try to make some pictures to make it easier to understand what is happening.

Sorry to resurrect an old thread, but I'm still having similar issues and wouldn't like to create a new thread on what is almost the same subject. My ASIAIR + Ioptron CEM60 combo still works the way described earlier in the thread, however, I would like to make use of the CEM60's built in USB hub / pass through. That would allow me to eliminate all potential cable snags. The problem is, ASIAIR cannot seem to find the mount when I try to do this, and I'm having trouble locating the problem. It might be best if I describe what works and what doesn't: 1. RS232 - USB -cable from the mount's RS232 port straight to ASIAIR. WORKS 2. RS232 - USB -cable from the mount's RS232 port to a USB A/B adapter, connecting to the mount USB (next to the 12V input for the saddle ports), then regular USB from the saddle to ASIAIR. NO CONNECTION 3. RS232 - USB -cable from the mount's RS232 port to the saddle USB port, then via USB A/B -adapter and a regular USB cable to the ASIAIR. WORKS So, connecting the cables the other way around helps it find connection, but in that case the cables are obviously the wrong way. I confirmed this by running my laptop mouse through the mount pass through. Same thing, works one way, doesn't the other. What on earth is this nonsense? 😃 I would really appreciate any help.

The white-greenish auroras are by far the most common ones, and the brightest. My understanding is that this is oxygen emitting at 557,7 nm. Sometimes there are also reddish colors, which Wikipedia tells me are also from excited oxygen atoms at 630 nm. These are usually dimmer at least to the eye, but surely bright enough to destroy long exposure photos, when they occur. There are also other possible wavelengths, including IR. The bandpasses for my particular filters are: A wide bandpass filter like the Moon & Skyglow will basically let in all the aurora glow as well. The Optolong, having a more narrow bandpass, might not. However, both the green and red aurora wavelengths are "in the neighborhood" of O3 and H-alpha wavelengths. For good quality narrowband filter they will never be a problem, I´m sure. For an OSC-oriented double bandbass filter like the l-enhance, not so sure. If it works as the graph indicates, it should block the auroras. If it is a bit wider than advertised, some might get through. I guess we will find out, weather permitting. 😀

This doesn't seem like a common headache around here. 😀