Do I have to block out any pictures of the sun and moon in my meteorology textbook (and if so how)?
This is a tough question. It is controversial, some poskim say that ne should block out the pictures, at least partially, so that it doesn’t look like a full sun, however other poskim and it it seems that the minhag is not to have to do this. Even if you would want to do like the stricter opinion, all you would have to do is take a marker and make a line across part of the edge of the sun or make a dot in the middle of it, so it doesn’t look whole. The reason being that the normal appearance of the sun is a whole ball, (unlike the moon that is normally seen in various stages) it isn’t considered as make an image of something that appears in the heavens. See sources.
The gemorah Avoda Zara 42b-43b, discusses the prohibition not to make images of anything image that exist in the heavens, this includes images of angles, celestial beings, the image of humans, or the sun, moon or stars. This is a biblical prohibition, however by rabbinical injunction we are also not allowed to keep them in our possession because of maris ayin- it appears to having an avoda zara in our possession. Since our issue is only regarding keeping the image we are dealing with an issur d’baronon, nevertheless on the surface it would appear that it should not be allowed, and this is the opinion of some poskim.
There are perhaps a few factors that might lend themselves to be lenient in this case. The Shulchan Aruch Y:D 141-4 writes regarding human images, that there is a difference between an image that protrudes and a flat one, that a flat image is permitted. Ramban, Bach, Taz (ibid 12) and Chochmas Adom (85 -8) however argue with this. All agree that a flat image of the sun moon, etc. is forbidden to make, the reason being because the way we perceive the sun etc. from earth is always flat.
One of the potential rationales to permit keeping an image that we are not allowed to make is based on the Chochmas Adom 85- 6 who says that nowadays that people don’t worship humans images, and even though that do, it is a specialized image, therefore he rules that it is permitted to keep a human images in ones possession (except for the specialized image). It could be that some people rely on this for pictures of the sun. However it is hard to compare the two, because there are those that worship the sun even nowadays, therefore his rationale seemingly would not apply to images of the sun. Besides this, the Chochmas Adom in the paragraph right before stated that w may not make or keep an image of the sun, and he does not mention that his heter applies to anything but human images. Therefore it is difficult to apply his heter for this.
Another possible rationale for leniency would be perhaps because the Shulchan Aruch (ibid) states that it is permitted to make images for educational purposes, similar to Rabban Gamliel who had images of the moon in his attic. The reason he was allowed to was because it was for educational purposes. Therefore being that the meteorology book is for educational purposes there might be room to include this is that heter. This however is also not so simple, because says that it is permitted when it is “lilmod lihovin u’lihoros” when it is in order to learn in order to give a halachic ruling”. In fact numerous poskim (Chasam Sofer Shut Y:D 128, Divrei Chachomim Y:D 45, Minchas Yitzchok 10-72, R’ Reisman shlit”a in the name of R’ Pam Zt’l) say that it isn’t merely for any educational purpose, especially if it isn’t torah related.
Another reason for possible leniency would be that although it is controversial, (Chochmas Adom 85-6, Shevet Halevi 7-134(6), Chut Shani Pesach pg. 237, rule that it should not be kept), there are a number of poskim that say that if the image is not protruding that it is permitted to keep. See Maharit 2- Y:D 35 who brings the opinion of the Ran who permits this, Darcei Teshuva Y:D 141- 34 who brings Shut Lechem Rav, regarding pictures of the sun or moon that were drawn on a kesubah that if it was already done that if it was already written that it is permitted to keep, Kitzur Shulchan Aruch 168-1, and it is also brought in the name of R’ Eliyashiv zt”l Piskei Halachos- (Kroll) Y:D 73, that if t was already made it may be kept.