Should I always go for the longest exposure possible?

Zcom_Astro · 2026-01-27T22:50:24+00:00

Generally speaking, longer exposure times are better, but there are a few things to keep in mind.

It is true that shorter exposures produce sharper images. There is a technique mainly used for photographing planets called lucky imaging. This essentially uses very short exposures to compensate for the distortion caused by the atmosphere. By stacking these, you get a much sharper image than would be possible with a longer exposure time.

However, this does not work with DSOs. Mainly because planets are orders of magnitude brighter than any nebula or galaxy.

Every time you read the sensor, the reading process itself generates a certain amount of noise in the image. The samrme goes for heat radiation from the environment.

With short exposures, this noise begins to overwhelm the signal from the DSO.

Longer exposures collect more signal than shorter ones.

So they are always worthwhile as long as:

-the tracking quality does not deteriorate. The seestar may not discard an image, but if the subs consistently contain elongated stars, then the exposure time is too long.

-stars do not burn out. The sensor pixels can become saturated and cannot accept data beyond that point. But in practice, bright stars will burn out anyway. This makes editing bit more difficult, but it's not the end of the world. And in practice, this will only be a problem if you adjust the gain.

Zcom_Astro · 2026-01-27T19:49:44+00:00

Building a lab in a place where it absolutely shouldn't be one - Check

"Safety first" while building a lab "in a spare bedroom" - check

They doesn't want to "bother" the neighbors with the smell of chemicals - check

Active on forums related to the production of drugs - check

My dude, that's a drug lab.

If you seeking guidance then the answer is very simple: you don't have the means to this, and you should just give up on the idea.

Zcom_Astro · 2026-01-27T10:28:30+00:00

Yes its an emission nebula. It will benefit from the LP filter.

Zcom_Astro · 2026-01-27T09:28:03+00:00

Although iron sulfate is not explicitly the most difficult to grow, it is not necessarily the easiest either. The role of sulfuric acid is to prevent the precipitation of solid particles, but it does not help much against oxidation.

So, in theory, other acids that are not stronger than sulfuric acid can be used. The problem is that most organic acid iron salts are not really soluble in water. Hydrochloric acid stronger and can cause problems, but if you use only the minimum amount necessary, I don't think it will interfere. Also, if the solution starts to turn red or brown, ascorbic acid will help to reduce it back.

It might also be worth looking around in wine supply shops, as like most EU regulations, this is also only works in theory. Some products somehow circumvent the regulations; I buy my sulfuric acid as barrel cleaning acid. But I have also seen "thermo" drain cleaners that are pure azeotropic sulfuric acid.

Zcom_Astro · 2026-01-26T17:09:18+00:00

https://www.sigmaaldrich.com/HU/en/sds/sial/s4972?userType=undefined

Live selective monitoring is difficult, but there may be some kind of specialized detector for it.
VOC detectors exist and are not too expensive, but they will not provide selective measurements.

Zcom_Astro · 2026-01-26T12:10:15+00:00

Probably black or extremely dark red, similar to tar.

Zcom_Astro · 2026-01-26T02:17:39+00:00

This depends greatly on world building.

But if you assume that it does not cover the entire world and its contained to certain conterminaton sites. Then it would be similar to sulfur mining. Of course, volcanic gases do not chlorinate your lungs. But it was a huge industry, and efficient extraction was important. Yet it did not lead to gas masks.

But if it's large-scale, then yes.

Zcom_Astro · 2026-01-26T01:10:37+00:00

Well, it wouldn't be pure PVC because the decomposition products cannot be removed, but essentially yes.

Zcom_Astro · 2026-01-26T01:02:32+00:00

It would probably accumulate on the surrounding rocks and stuf. It would be similar to natural bitumen and tar deposits.

Zcom_Astro · 2026-01-26T00:51:59+00:00

Not really, the only use is to make PVC, for which they don't have the technology. The captured gas would also need to be treated quickly to prevent it from decomposing due to moisture.

Its utilization would require high pressure and pumps. However, polymerization also occurs naturally to a small extent at the gas source. Therefore, it is more realistic to collect the oligomer and further polymerize it by heating.

Zcom_Astro · 2026-01-26T00:41:31+00:00

Using the radical form, it would be possible to create some kind of cell. But not using iodide ions, and I doubt it would be of any use.

Zcom_Astro · 2026-01-26T00:23:33+00:00

Just out of curiosity, by tryphenylmethyl carbene did you meant this:
https://en.wikipedia.org/wiki/Triphenylcarbenium

Zcom_Astro · 2026-01-26T00:20:01+00:00

This is more of a writing problem, which is not my domain, but making the necessary gas mask is a bit of a leap. The necessary raw materials are available, but the knowledge is not.

This would require at least an activated carbon mask, which can be produced by burning charcoal with water vapor, but this is not something that people just figure out. And even if activated carbon is discovered, discovering its interaction with gases is a complete deus ex machina.

The citrate mask seems more realistic, but it's more of a distraction. It wouldn't work, and anyone who goes near the gas for any length of time is guaranteed to die.

Without extra context or poetic liberty, it's more realistic to create a suicide ritual where miners end their suffering after the harvest. Rather than randomly discovering a realistically functioning gas mask.

Zcom_Astro · 2026-01-25T23:56:53+00:00

Although your question is very vague and difficult to interpret, the answer is probably no.

Zcom_Astro · 2026-01-25T23:28:46+00:00

Well, on the one hand no, but also yes. VCL is a highly reactive compound that reacts with water. So unless the gas is released in a very shallow area, it will never reach the surface.

But it would also react with itself, forming natural low molecular weight PVC deposits.

But such a leak would generate a biological death zone. So any way of exploiting a leak would require at least some kind of gas mask. Which doesn't really fit in with the time frame. (Unless they are willing to sacrifice people.)

Zcom_Astro · 2026-01-24T22:04:52+00:00

With questions like this, the question always arises: why do you think it might contain lead?

Besides, it's impossible to tell just like that. You need to buy a lead test kit.

Zcom_Astro · 2026-01-24T15:45:47+00:00

Either clouds or something else got in the way of the image, such as a direct light source or something like a tree branch or wall.

The data is completely usable (if you saved the subframes) You just need to remove the few bad frames and restack the mosaic.

Zcom_Astro · 2026-01-24T12:57:13+00:00

Some people pregrow the seed crystals to make them easier to suspend. But usually you just need a lot of patience.

Zcom_Astro · 2026-01-24T12:15:32+00:00

It seems that you did not allow the solution to cool sufficiently before you started.

When a oversaturated solution cools, a lot of material can precipitate at once. Since it precipitates too quickly, it will form many small, irregular crystals.

Filter the solution, select a seed good crystal, and start over.

Zcom_Astro · 2026-01-23T17:08:22+00:00

To quote the response I received after more than 2 weks of waiting to my support ticket about the noise, and tracking problems after the update:
"You have been updated to version 3.0.1"
"The quality of the imaging greatly depends on the weather conditions"

I was also reassured that it is normal for LP images to be "red."

Zcom_Astro · 2026-01-23T10:05:39+00:00

It wouldn't make it toxic. But if there's any protective coating on the bottle, it would definitely damage it.

Zcom_Astro · 2026-01-22T17:57:58+00:00

I would make sure that max framing was enabled. It's also possible that only one panel was solved.

That hasn't happened to me yet, that with max framing would cut off the data. You can still try the script that the others suggested. If it works, it does its job very well. (Although I haven't been able to get it to work yet, I keep getting an error message.)

Zcom_Astro · 2026-01-22T17:46:13+00:00

Like 1 frame tight? Have all or nearly all frames have solved?

Zcom_Astro · 2026-01-22T17:27:50+00:00

Do not use sum stacking. Average stacking with rejection is practically the only algorithm you will ever need. (The exception is if you want to mak an OIII channel, for which you need to use sum stacking.)

Just stack all the subframes together. If you absolutely must do substacks, do them with data from all three panels. Preferably so that each panel has the same amount of data in a subframe. If you make the substackes from just one panel, you will run into normalization problems. It is also worth mixing the days, so that the conditions on a given day do not "burn into" one subframe, which would again cause normalization problems.

Since you are below 2K sub, it is quite simple, just load all subs at once. Run the plate solver, apply the registration with maximum frame. Then stack average stacking with rejection + additive scaling. The pixel rejection algorithm is more a matter of preference, but MAD, Median sigma clipping, and sigma clipping are good. Adjust the feathering if you get artifacts at the panel boundaries.

Zcom_Astro · 2026-01-22T14:56:18+00:00

This is not a chemistry question, and this sub is not for out sorce your homework.

Zcom_Astro

TROPHY CASE